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Full text of "The Neotropical land snail genera: Labyrinthus and Isomeria (Pulmonata, Camaenidae)"

LIBRARY OF THE 

UNIVERSITY OF ILLINOIS 

AT URBANA-CHAMPAIGN 



530.5 

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v.50 

CC2D.3 




..niUKAL HISTORY 
SURVEY 



t 

50 THE NEOTROPICAL LAND SNAIL GENERA 

3 LABYRINTHUS and ISOMERIA 

(PULMONATA, CAMAENIDAE) 



ALAN SOLEM 



FIELDIANA: ZOOLOGY 

VOLUME 50 

Published by 

FIELD MUSEUM OF NATURAL HISTORY 

MAY 31, 1966 



liB2A°Y 



FIELDIANA: ZOOLOGY 

A Continuation of the 

ZOOLOGICAL SERIES 

of 

FIELD MUSEUM OF NATURAL HISTORY 



VOLUME 50 




FIELD MUSEUM OF NATURAL HISTORY 
CHICAGO, U.S.A. 
1966 



THE NEOTROPICAL LAND SNAIL GENERA 

LABYRINTHUS and ISOMERIA 

(PULMONATA, CAMAENIDAE) 



THE NEOTROPICAL LAND SNAIL GENERA 

LABYRINTHUS and ISOMERIA 

(PULMONATA, CAMAENIDAE) 



ALAN SOLEM 

Curator, Division of Lower Invertebrates 



FIELDIANA: ZOOLOGY 

VOLUME 50 

Published by 

FIELD MUSEUM OF NATURAL HISTORY 

MAY 31, 1966 



Library of Congress Catalog Card Number: 66-1 91 !& 



PRINTED IN THE UNITED STATES OF AMERICA 
BY FIELD MUSEUM PRESS 



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„■ SO 



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CONTENTS 

PAGE 

List of Text Figures 7 

List of Tables 9 

Introduction 11 

General and Acknowledgments 11 

Material 13 

Life History and Ecology 19 

Gross Anatomy 20 

Classification 34 

Fossil Record 36 

Systematic Review 

Labyrinthus 37 

Classification 42 

Review of the species 44 

Group of Labyrinthus isodon 44 

Key to the Group 46 

Labyrinthus triplicatus (von Martens) 47 

Labyrinthus quadridentatus (Broderip) 50 

Labyrinthus q. quadridentatus (Broderip) 51 

L. q. biolleyi new subspecies 52 

Labyrinthus tamsianus (Dunker) 53 

Labyrinthus leucodon (Pfeiffer) 55 

Labyrinthus I. leucodon (Pfeiffer) 55 

Labyrinthus I. umbrus Thompson 58 

Labyrinhus magdalenensis new species 59 

Labyrinthus dunkeri (Pfeiffer) 60 

Labyrinthus isodon (Pfeiffer) 62 

Labyrinthus vexans (Dohrn) 65 

Labyrinthus manueli Higgins 66 

Group of Labyrinthus raimondii 67 

Key to the Group 70 

Labyrinthus sieversi (von Martens) 71 

Labyrinthus sp 71 

Labyrinthus ellipsostomus (Pfeiffer) 73 

Labyrinthus diminutus Gude 75 

Labyrinthus pronus Pilsbry 78 

Labyrinthus leprieurii (Petit) 79 

Labyrinthus tarapotoensis (Moricand) 80 

Labyrinthus t. tarapotoensis (Moricand) 80 

Labyrinthus t. baeri Dautzenberg 81 

3 



CONTENTS 

PAGE 

Labyrinthus raimondii (Philippi) 81 

Labyrinthus furcillalus (Hup6) 86 

Labyrinthus bifurcatus (Deshayes) 87 

Group of Labyrinthus aenigmus 87 

Key to the Group 89 

Labyrinthus aenigmus (Dohrn) 89 

Labyrinthus clappi Pilsbry 90 

Labyrinthus otostomus (Pfeiffer) 91 

Labyrinthus o. otostomus (Pfeiffer) 91 

Labyrinthus o. bogotensis (Pfeiffer) 92 

Labyrinthus o. assimilans E. A. Smith 93 

Group of Labyrinthus unciger 94 

Labyrinthus unciger (Petit) 95 

Labyrinthus creveauxianus (Ancey) 100 

Group of Labyrinthus otis (Lightfoot) 102 

Key to the Group 103 

Labyrinthus otis (Lightfoot) 105 

Labyrinthus o. otis 105 

Labyrinthus o. orthorhinus Pilsbry 108 

Labyrinthus subplanatus (Petit) 114 

Labyrinthus s. subplanatus (Petit) 114 

Labyrinthus s. erectus (Mousson) 116 

Labyrinthus s. sipunculatus (Forbes) 119 

Labyrinthus plicatus (Born) 122 

Labyrinthus marmatensis Pilsbry 124 

Species of uncertain affinity 125 

Labyrinthus euclausus Beddome 125 

Labyrinthus sharmani (Gude) 126 

Isomeria 126 

Classification 130 

Review of the species 131 

Key to the Species Group 131 

Group of Isomeria inexpectata 132 

Isomeria inexpectata new species 132 

Group of Isomeria bituberculata 134 

Key to the Group 135 

Isomeria medemi new species 136 

Isomeria basidens (Mousson) 138 

Isomeria b. basidens (Mousson) 138 

Isomeria b. gudeana (Ancey) 139 

Isomeria neogranadensis (Pfeiffer) 140 

Isomeria bituberculata (Pfeiffer) 142 

Isomeria juno (Pfeiffer) 145 

Isomeria bourcieri (Pfeiffer) 148 

Isomeria hartwegi (Pfeiffer) 150 

Group of Isomeria subelliptica 151 

Key to the Group 152 

Isomeria morula (Hidalgo) 152 



CONTENTS 5 

PAGE 

Isomeria anodonta Pilsbry 153 

Isomeria aloagana Jousseaume 155 

Isomeria continua (Pfeiffer) 155 

Isomeria minuta new species 157 

Isomeria subelliptica (Mousson) 159 

Group of Isomeria meobambensis 160 

Key to the Group 161 

Isomeria meobambensis (Pfeiffer) 161 

Isomeria gealei (Smith) 162 

Isomeria aequatoria (Pfeiffer) 164 

Isomeria meyeri (Strubell) 164 

Group of Isomeria oreas 165 

Key to the Group 167 

Isomeria oreas (Koch) 167 

Isomeria kolbergi Miller 172 

Isomeria triodonta (d'Orbigny) 174 

Isomeria stoltzmanni (Lubomirski) 176 

Isomeria jacksoni new name 178 

Isomeria cymatodes (Pfeiffer) 180 

Isomeria for diana (Pilsbry) 183 

Isomeria scalena (von Martens) 183 

Isomeria aequatoriana (Hidalgo) 184 

Isomeria globosa (Broderip) 190 

Nomina dubia 

Isomeria calomorpha (Jonas) 193 

Isomeria fauna (Philippi) 194 

Isomeria equestrata (Moricand) 194 

Zoogeography 196 

Distribution of Labyrinthus 196 

Altitudinal zonation 204 

Distribution of Isomeria 206 

Altitudinal zonation 209 

Comparative remarks 211 

Summary 213 

References 215 

Index 217 



List of Illustrations 

PAGE 

1. Jaws of Labyrinthus unciger and L. otis orthorhinus 22 

2. Pallial regions of Labyrinthus otis orthorhinus and L. diminutus .... 24 

3. Pallial regions of Isomeria globosa and Labyrinthus unciger 25 

4. Genitalia of Isomeria globosa 26-27 

5. Genitalia of Labyrinthus unciger 28 

6. Genitalia of Labyrinthus otis orthorhinus 29 

7. Genitalia of Labyrinthus diminutus 30 

8. Interior of penial region in Labyrinthus diminutus 31 

9. Apertural zones in Labyrinthus 39 

10. Apertures of Labyrinthus triplicatus, L. quadridentatus and L. magdale- 

nensis 48 

11. Shells of Labyrinthus triplicatus, L. quadridentatus and L. magdalenensis . 49 

12. Apertures of Labyrinthus tamsianus, L. leucodon 56 

13. Shells of Labyrinthus tamsianus, L. leucodon and L. dunkeri 57 

14. Apertures of Labyrinthus dunkeri, L. isodon, L. vexans and L. manueli . 62 

15. Shells of Labyrinthus isodon, L. vexans, L. manueli and L. sieversi ... 63 

16. Apertures of Labyrinthus sieversi, L. leprieurii 72 

17. Shells of Labyrinthus leprieurii and L. ellipsostomus 73 

18. Aperture of Labyrinthus ellipsostomus 74 

19. Shells of Labyrinthus sp. and L. diminutus 76 

20. Labyrinthus pronus 78 

21. Apertures of Labyrinthus diminutus, L. tarapotoensis, L. raimondii, L. fur- 

cillatus and L. bifurcatus 82 

22. Shells of Labyrinthus tarapotoensis, L. raimondii, L. furcillatus and L. bi- 

furcatus 83 

23. Apertures of Labyrinthus aenigmus, L. clappi, and L. otostomus .... 88 

24. Shells of Labyrinthus aenigmus, L. clappi, and L. otostomus 89 

25. Parietal lips in Labyrinthus otostomus 92 

26. Labyrinthus otostomus assimilans and L. sharmani 94 

27. Shells of Labyrinthus unciger and L. creveauxianus 96 

28. Aperture of Labyrinthus creveauxianus 97 

29. Palatal tooth variation in Labyrinthus unciger 98 

30. Shells of Labyrinthus otis 110 

31. Supraperipheral grooves in Labyrinthus otis Ill 

32. Apertures in Labyrinthus subplanatus and Labyrinthus plicatus . . . .114 

33. Shells of Labyrinthus subplanatus 115 

34. Apertures of Labyrinthus sipunculatus and L. plicatus 120 

35. Variation of peripheral notch in Labyrinthus sipunculatus 121 

36. Shells of Labyrinthus plicatus and L. marmatensis 124 

37. Isomeria inexpectata 133 

38. Isomeria medemi 137 

39. Isomeria basidens 140 

7 



8 LIST OF ILLUSTRATIONS 

PAGE 

40. Apertures of Isomeria basidens, I. neogranadensis and /. bituberculata . 141 

4 1 . Shells of Isomeria neogranadensis, I. bituberculata, I. juno and /. hartwegi . 146 

42. Shells of Isomeria juno, I. hartwegi and /. bourcieri 147 

43. Isomeria aloagana 154 

44. Shells of Isomeria anodonta and /. continua 156 

45. Isomeria minuta 158 

46. Isomeria subelliptica 159 

47. Shells of Isomeria meobambensis, I. gealei and J. aequatoria 163 

48. Shells of Isomeria oreas, I. kolbergi and /. triodonta 170 

49. Apertures of Isomeria oreas, I. kolbergi and /. triodonta 171 

50. Isomeria stoltzmanni 177 

51. Shells of Isomeria jacksoni, I. cymatodes and J. fordiana 180 

52. Apertures of Isomeria jacksoni, I. cymatodes and /. fordiana 181 

53. Shells of Isomeria aequatoriana, I. globosa, I. scalena and /. fauna . . . 186 

54. Apertures of Isomeria aequatoriana, I. scalena and /. fauna 187 

55. Isomeria aequatoriana 189 

56. Apertures of Isomeria globosa 192 

57. Distribution of L. isodon complex 197 

58. Distribution of Labyrinthus raimondii complex 199 

59. Distribution of Labyrinthus otis complex 201 

60. Altitudinal range in Labyrinthus 203 

61. Altitudinal range in Isomeria 210 



List of Tables 

PAGB 

I. Specimens examined of Labyrinthus 13 

II. Specimens examined of Isomeria 14 

III. Representation in collections 15 

IV. Size and shape variation in Labyrinthus triplicatus, L. q. quadridentatus, 

L. q. biolleyi, L. tamsianus, L. I. leucodon and L. magdalenensis ... 54 

V. Size and shape variation in Labyrinthus dunkeri and L. manueli ... 64 

VI. Size variation in Labyrinthus raimondii complex 69 

VII. Size and shape variation in Labyrinthus ellipsostomus, L. diminutus, 

L. tarapotoensis baeri and L. furcillatus 77 

VIII. Size and shape variation in Labyrinthus raimondii, L. clappi, L. oto- 

stomus bogotensis and L. creveauxianus 85 

IX. Size and shape variation in Labyrinthus unciger 101 

X. Size and shape variation in Labyrinthus o. otis and L. o. orthorhinus . . 107 

XI. Size and shape variation in Labyrinthus o. orthorhinus 109 

XII. Size and shape variation in Labyrinthus s. subplanatus, L. s. sipuncu- . 

latus and L. plicatus 118 

XIII. Size and shape variation in Isomeria inexpectata, I. juno, I. bituberculata 

and J. meobambensis 143 

XIV. Size and shape variation in Isomeria oreas, I. kolbergi and /. jacksoni . 169 

XV. Size and shape variation in Isomeria cymatodes, I. aequatoriana and 

/. globosa 185 

XVI. Transandean distributions in Central Ecuador 207 



INTRODUCTION 1 

This review of the mainland Neotropical Camaenidae had its ori- 
gins in an attempt to evaluate infra-specific variation in shells of 
Panamanian Labyrinthus. It soon developed into a synoptic revi- 
sion, which also serves to emphasize that 1) taxonomic knowledge of 
land snails is very slight; and 2) existing collections of land mollusks 
are totally inadequate for modern systematic research. Despite ac- 
cess to the major molluscan collections of the world, 48.6 per cent of 
the species and subspecies were represented by fewer than 10 exam- 
ples, and only five taxa (7.1 per cent) by more than 100 specimens. 
Geographic ranges are obviously poorly understood in view of the 
lack of material. Actually, there are twenty-one species and sub- 
species (30.0 per cent) for which we lack any exact locality or for 
which the geographical terms are vague enough that they cannot now 
be placed within a fifty-mile radius. Thirteen other species (18.5 per 
cent) have been reported only from essentially the type locality. 
Many of the species in both categories are based on single collections 
made in the last century. For half of the taxa we scarcely have 
enough data for alpha taxonomy. 

Because of scarcity of material and fragmentary distributional 
data, this paper is basically a summary of inadequate knowledge with 
numerous suggestions as to possibilities for research that would re- 
quire field studies. Of these problems, perhaps the most important 
from an evolutionary viewpoint is how to classify the species. An 
altitudinally correlated separation into Labyrinthus (with the aper- 
ture grossly obstructed by teeth) and Isomeria (with the aperture 
only slightly obstructed by teeth) has been adopted, although dis- 
sections of the few available species suggest that the transition from 
obstructed to open aperture (or vice versa) happened more than once. 
Many distributional and ecological problems are mentioned in the 
body of the text. 

Since the original descriptions and illustrations are scattered 
through publications available only in the largest libraries and mu- 

1 While this paper was in press, Chicago Natural History Museum adopted the 
name Field Museum of Natural History. In this paper the catalog designations 
remain CNHM. 

11 



12 FIELDIANA: ZOOLOGY, VOLUME 50 

seums, I have provided photographs of the shells and short diagnoses 
covering the main differentiating characters. The resulting synoptic 
review will allow identification of the species and provides available 
background data for field studies relating to variation and problems 
of classification. Perhaps the main function I can hope to serve, 
however, is to indicate the enormous opportunities for systematic 
research presented by the land mollusks and the equally great prob- 
lems caused, in part, by the present lack of adequate collections. 

The only previous review of the American camaenids is by Pilsbry 
in the Second Series of the Manual of Conchology. The illustrated 
accounts are scattered through several volumes, but summarized in 
Pilsbry (1894, pp. 84-143). The mainland American genera were sur- 
veyed by Pilsbry (1889, pp. 135-176). He reviewed 30 species of 
Isomeria and 22 Labyrinthus, compared with the 28 species in each 
genus recognized below. Despite having "seen scarcely half of the 
species" of Isomeria, Pilsbry 's account is basically correct. Neces- 
sary alterations in synonymy are primarily caused by rediscovery of 
older species and examination of material collected subsequent to 
Pilsbry's study. 

Many people are responsible for the success of this project. For 
permission to study all materials in collections in their charge, I am 
deeply indebted to Dr. Harald A. Rehder, United States National 
Museum; Dr. William J. Clench, Museum of Comparative Zool- 
ogy, Harvard; Dr. R. Tucker Abbott, Academy of Natural Sciences, 
Philadelphia; Dr. E. Fischer-Piette, Museum National d'Histoire 
Naturelle, Paris; Dr. H. E. Coomans, Zoologisch Museum, Amster- 
dam; Mr. Norman Tebble, British Museum (Natural History); 
Dr. A. Zilch, Senckenbergische Naturforschende Gesellschaft, 
Frankfurt-a.-M.; Dr. H. Burla, Zoologisches Museum der Universi- 
tat, Zurich; Dr. A. Rodger Waterston, Royal Scottish Museum, 
Edinburgh; Dr. Tron Soot-Ryen, Zoological Museum, Oslo; and Dr. 
Juan Jose Parodiz, Carnegie Museum, Pittsburgh. For the loan of 
selected materials from their collections, I wish to thank Dr. Lothar 
Forcart, Naturhistorisches Museum, Basel; Dr. A. Riedel, Polska 
Akademia Nauk; Dr. R. Wright Barker, Houston; and Mr. Ralph 
Jackson, Cambridge, Maryland. Mr. Norman Tebble and Mr. John 
Peake, British Museum (Natural History) located and arranged for 
photographs of the types shown in Figure 26. I am deeply grateful 
to the Trustees of the British Museum (Natural History) for permis- 
sion to publish these photographs. Loan of a set of types from 
Musee d'Histoire Naturelle de la Ville, Neuchatel, was facilitated by 



SOLEM: NEOTROPICAL LAND SNAILS 13 

Dr. L. Forcart, Basel, who visited Neuchatel to locate the specimens 
and arranged the requested loan. 

The largest volume of material from a single source was made 
available by Mr. Ralph Jackson. In addition, many of the specimens 
in North American museums were exchanges from Mr. Jackson. 
Without access to his material, this paper could not have been writ- 
ten, since other collections contained too little material to warrant 
even this incomplete a study. 

The many fine drawings of the apertural characters in Labyrinthus 
and most of the anatomical figures are by Miss Marian Pahl, Staff 
Artist of Field Museum of Natural History. Statistical calculations 
were made by Miss Robin Zimmerman, a student at Roosevelt Uni- 
versity. For the laborious job of checking citations for accuracy and 
for typing and retyping manuscript, I am indebted to my wife and 
to Mrs. Rita Mecko, clerk-typist in the Division of Lower Inverte- 
brates. Photographs were made primarily by Homer Holdren, Pho- 
tographer, Field Museum of Natural History, with my assistance, or 
by myself during visits to other institutions. 

Material 

A total of 1,992 adult and juvenile specimens were examined, 
1,152 belonging to species classified as Labyrinthus and 840 to spe- 
cies placed in Isomeria. All specimens in nine museums and one pri- 

Table I 
Specimens examined of Labyrinthus 



L. triplicatus 


46 


L. raimondii 


130 


L. q. quadridentatus 


8 


L. furcillatus 


15 


L. q. biolleyi 


6 


L. bifurcatus 


2 


L. tamsianus 


38 


L. aenigmus 


6 


L. 1. leucodon 


44 


L. clappi 


17 


L. 1. umbrus 


2 


L. o. otostomus 


1 


L. magdalenensis 


5 


L. o. bogotensis 


18 


L. dunkeri 


47 


L. o. assimilans 


2 


L. isodon 


6 


L. unciger 


121 


L. vexans 


3 


L. creveauxianus 


32 


L. manueli 


31 


L. o. otis 


33 


L. sieversi 


3 


L. o. orthorhinus 


268 


L. sp. 


2 


L. s. subplanatus 


15 


L. ellipsostomus 


28 


L. s. erectus 


10 


L. diminutus 


33 


L. s. sipunculatus 


17 


L. pronus 


3 


L. plicattis 


110 


L. leprieurii 


17 


L. marmatensis 


12 


L. t. tarapotoensis 


9 


L. euclausus 


— 


L. t. baeri 


11 


L. sharmani 


1 



14 



FIELDIANA: ZOOLOGY, VOLUME 50 



vate collection were examined, but only rare material, field collec- 
tions, or types were borrowed from six additional sources. 







Table II 






Specimens examined of Isomeria 




/. inexpectata 


3 


/. gealei 


7 


I. medemi 


2 


I. aequatoria 


22 


I. b. basidens 


1 


I. meyeri 


— 


I. b. gudeana 


5 


I. oreas 


99 


I. neogranadensis 


1 


I. kolbergi 


101 


I. bituberculata 


98 


I. triodonta 


44 


I. juno 


56 


I. stoltzmanni 


2 


I. bourcieri 


65 


I. jacksoni 


20 


I. hartwegi 


13 


I. cymatodes 


98 


I. morula 


— 


I. fordiana 


5 


I. anodonta 


1 


I. scalena 


5 


I. aloagana 


— 


I. aequatoriana 


75 


I. continua 


16 


I. globosa 


78 


I. minuta 


1 


I. calomorpha 


— 


I. subelliptica 


3 


I. fauna 


2 


I. meobambensis 


16 


I. equestrata 


1 



Throughout the text, the following abbreviations indicate the 

source of the material mentioned: 

ANSP Academy of Natural Sciences, Philadelphia 

Barker R. Wright Barker collection, Houston 

Basel Naturhistorisches Museum, Basel 

Brit. Mus. British Museum (Natural History), London 

CM Carnegie Museum, Pittsburgh 

CNHM (Chicago Nat. Hist. Mus.) Field Museum of Natural History 

Edinburgh Royal Scottish Museum, Edinburgh 

Jackson Ralph Jackson collection, Cambridge, Maryland 

MCZ Museum of Comparative Zoology, Harvard 

Neuchatel Musee d'Histoire Naturelle de la Ville, Neuchatel 

Paris Museum National d'Histoire Naturelle, Paris 

SMF Senckenbergisches Museum, Frankfurt-a.-M., Germany 

USNM United States National Museum, Washington, D. C. 

Warsaw Polska Akademia Nauk, Warsaw 

ZMA Zoologisch Museum, Amsterdam 

Zurich Zoologisches Museum der Universitat Zurich 

Supplementary material of interest undoubtedly exists in the muse- 
ums of Berlin, Brussels and Madrid, and several unrecognized types 
may remain in the unlabeled miscellany of the British Museum (Nat- 
ural History), London. The types of Isomeria morula, I. aloagana 
and I. meyeri need to be located and refigured, but there is little 
doubt concerning the identity of the other species whose types were 
not consulted. 

Shortly before this paper was sent to the printers, Dr. Lothar 
Forcart informed me that the Naturhistorisches Museum, Basel, 



SOLEM: NEOTROPICAL LAND SNAILS 15 

had just received the collection of the late Dr. P. Bohny, which in- 
cluded the conchological cabinet of the Swiss botanist Edmond 
Boissier (1810-1885). Included in the latter collection was type ma- 
terial of three Labyrinthus — one specimen of L. tamsianus received 
from Dunker; one specimen of L. leprieurii received from Petit; and 
two specimens of L. unciger received from Petit. Measurements fur- 
nished by Dr. Forcart showed the specimens fell within the range of 
variation reported below. Whether these specimens should be desig- 
nated lectotypes or not is beyond the scope of this study, since pos- 
sibly other authentic material exists in other museums. 

Including incertae sedis, there are 70 taxa. No material could be 
examined of five of these; fourteen are represented by only one or two 
individuals; and nine by three to five examples. Thus 40 per cent of 
the species and subspecies are represented by less than six specimens 
in the major molluscan collections of the world. An additional nine- 
teen species and subspecies are based on a sample of six to twenty 
individuals; seven taxa by twenty-one to forty shells; eight by forty- 
one to eighty; seven by eighty-one to 160; and only one unit, a sub- 
species (Labyrinthus otis orthorhinus) , by more than 160 specimens. 
Table III indicates the representation in the larger collections where 
all available material was examined. Ignoring the five incertae sedis, 









Table III 














Representation 


in Collections 




















EDIN- 








CNHM 


ANSP 


SMF 


USNM 


ZURICH 


BURGH 


MCZ 


JACKSON 


Taxa 


















Labyrinthus 


27 


27 


21 


25 


17 


16 


20 


4 


(36) 


















Isomeria 


18 


18 


19 


12 


16 


12 


7 


11 


(29) 


















Total (65) 


45 


45 


40 


37 


33 


28 


27 


15 


Sets 


















Labyrinthus 


104 


77 


76 


84 


23 


18 


45 


12 


Isomeria 


74 


56 


78 


35 


23 


16 


17 


59 



Total 178 133 154 119 46 34 62 77 

the collections with the greatest representation (CNHM and ANSP) 
had 69.3 per cent of the known species and the next most complete 
collection (SMF) 61.5 per cent of the taxa. The collections are 
strictly synoptic, CNHM averaging 3.94 sets per taxon; ANSP 2.96 
sets; and USNM 3.22 sets. 



16 FIELDIANA: ZOOLOGY, VOLUME 50 

Most of the sets contained only one or two specimens. The rea- 
son for this is historical. Modern museum collections consist mainly 
of material first obtained by amateurs and donated or sold to the in- 
stitutions upon the death of the owner. Even at the present time, 
most amateur collectors utilize long series of shells as trade items, 
exchanging for species not represented in their collection. This atti- 
tude also has prevailed among museums, and many of the larger sets 
may represent only part of the original sample. One or two speci- 
mens from the original sample will be found in several other museum 
and private collections throughout the United States and foreign 
countries. Often a possibly unconscious bias is introduced in the 
process of trading such materials. I will cite examples from only one 
species, although several were noticed. Seventeen shells of L. otis 
orthorhinus collected on Barro Colorado Island in January, 1936 are 
now MCZ 111160. Two shells, formerly part of that set, are Jackson 
4829, and four are in the ZMA. Others undoubtedly exist in other 
collections. The two in Ralph Jackson's collection and two of the 
four in the ZMA are smaller than all but three of the seventeen re- 
maining in the MCZ collection. Similarly, three shells from the Sala- 
manca Hydrographic Station set (MCZ 111166) now in the ZMA 
were the 2nd, 3rd and 7th smallest of the fourteen examples located. 
Selection of these smaller examples for "trading" undoubtedly biased 
the remaining sample in favor of large size. This probably explains 
the slightly larger (0.6 mm.) mean diameter of the MCZ Barro Colo- 
rado Island set (see Table X, p. 107), when compared with material 
collected in other years. Such a bias is not, of course, that simple, 
since "specimen quality" as well as size is involved in shell exchanges 
between amateurs. 

The net result is that originally large samples will be widely dis- 
tributed through exchange. Over the 100-year period that most of 
these species have been known, the sets will be reduced to scattered 
short series of one or two examples. In preparing such exchanges, 
the tendency in the past often has been to shorten the label, so that 
specimens originally part of the type set labeled "Frontino, Colom- 
bia at 6,000 feet elevation" (L. aenigmus), now are labeled "New 
Granada" (see p. 90). Occasionally the reverse happens. A shell of 
L. aenigmus with a collection label "New Granada" had the museum 
label expanded to "Andes near Frontino, Colombia." 

These facts are common knowledge to museum curators, but have 
been presented here as a cautionary note to non-museum taxono- 
mists who might wish to use data from the tables in statistical analy- 



SOLEM: NEOTROPICAL LAND SNAILS 17 

sis. It can be presumed that most of the sets in museum collections 
that contain more than six or seven examples and were collected more 
than ten or fifteen years ago, have had specimens "traded off" and 
are biased selections. Contrary to normal expectations, I feel that 
sets with five to six examples, usually not subject to such trading, 
present a more reliable sample in this study than the sets with ten or 
more examples. 

A special note must be given concerning material from Ralph 
Jackson's collection. For over twenty years he has had a collecting 
contact in Ecuador providing land and fresh-water shells. As a re- 
sult, his personal collection contains more than twice the number of 
Isomeria (251 shells) found in the largest museum collection (CNHM 
with 123 shells). At intervals his collector forwards material col- 
lected "in the vicinity of" a town. Mr. Jackson sometimes has had 
several repeated sendings over a period of several years from the same 
locality. These shells are grouped in the same set in his collection. 
This is in accord with past procedures in such museums as the Uni- 
versity of Michigan Museum of Zoology. While this greatly reduces 
their utility in statistical analysis, in the absence of adequate data, 
any data is useful. The analysis of variation in the long sets from 
the Jackson collection is valid only to the extent of showing the range 
in variation for a species from the vicinity of a town over a period 
of several years. In the case of Isomeria, much of the material in 
North American museum collections has been obtained in trade from 
Mr. Jackson. Careful checking of these traded sets shows no size 
bias, but an obviously successful attempt to provide "quality" speci- 
mens to his correspondents. In many cases, the traded material has 
been included in the statistical analysis. 

It can be argued that such biased samples and grouped year classes 
would make any statistical treatment of the data a waste of time. 
For both Labyrinthus unciger (Table IX, p. 101) and L. otis orthorhinus 
(Table X, p. 107), we have sets taken from the same locality at inter- 
vals over a twenty to twenty- three-year period. Size variation in 
these chronologically separated sets, representing several generations, 
is minimal. Hence, analysis of the sets has been considered necessary 
to give at least some idea of the range of variability. The probable 
extent of sample bias, however, does preclude the desirability of more 
sophisticated statistical analysis of the data. 

The above data clearly demonstrate that only synoptic collections 
of Isomeria and Labyrinthus exist and that these collections are to- 
tally inadequate for modern systematics. The present sad state of 



18 FIELDIANA: ZOOLOGY, VOLUME 50 

molluscan taxonomy is equally clearly demonstrated by the fact that 
even this inadequate material allowed major alterations in synony- 
mies, as well as the inevitable description of four new species, one 
new subspecies and proposal of one new name. 

Because they are large and easily spotted, these genera are, among 
the Neotropical land snail fauna, well represented in museum collec- 
tions. For most other Neotropical taxa, much less material is avail- 
able and even cruder systematic work is necessary. In order to correct 
this situation, massive collecting efforts are needed. Even casual 
collections by field zoologists interested in other groups can add valu- 
able material at our present level of knowledge. Particularly, col- 
lection of live material with subsequent preservation of the soft parts 
is desirable, since only seven of the fifty-six species of Labyrinthus 
and Isomeria have been dissected. Equally small proportions of other 
Neotropical land snail taxa are known by other than the empty shell. 

It took several generations of concentrated activity by bird and 
mammal collectors to provide adequate systematic collections of Neo- 
tropical species. No similar effort to accumulate equivalent mollusk 
collections seems probable, and adequate systematic work will have 
to depend on gradual accumulation of fortuitous collections by ver- 
tebrate zoologists, geologists, teachers and missionaries. I will be 
pleased to provide information on collection and preservation tech- 
niques to interested parties and will be glad to receive any Neotropical 
molluscan materials for deposit and study. 

Early collections of birds and mammals were taken "in the vicin- 
ity of" a cited locality. For most of the land snail collections, we have 
not progressed from this primitive stage. Ornithologists have been 
particularly active in trying to elucidate the altitudinal limits covered 
by these early, rather nebulous collections. Since many of the origi- 
nal collections of land snails were by early professional zoological col- 
lectors, the papers of de Schauensee (1948, pp. 251-342) for Colombia 
and Chapman (1926, pp. 703-722) for Ecuador have been most help- 
ful in indicating the probable altitudinal ranges encompassed by early 
localities. In the body of this study, data as to altitude have been 
presented without direct citation of these sources. They represent 
reasoned guesses as to the probable vertical range within which the 
shells were collected, and are in no way to be accepted as accurate 
citations. For other sets, apparently accurate altitudinal data were 
included on the field label. The resultant altitudinal ranges are thus 
only preliminary estimates or guesses as to the probable range. The 
general altitudinal separation of Labyrinthus and Isomeria is discussed 



SOLEM: NEOTROPICAL LAND SNAILS 19 

fully in the section on distribution (pp. 196-212) . Here it is worthwhile 
to record that we have practically no information on the phenomenon 
of altitudinal replacement. Labyrinthus unciger and L. creveauxianus 
may show such replacement in Northern Colombia. In the Sierra 
Nevada de Santa Marta there are four species — L. sieversi (300- 
5,500 feet), L. clappi (4,000-5,000 feet), Isomeria medemi (8,200- 
8,850 feet) and I. inexpectata (8,500-9,000 feet). These species live 
in different parts of the mountain range, except possibly L. clappi 
and 7. medemi, which may be altitudinally zoned. The only clear 
case of possible altitudinal zoning in a restricted area is the Rio Paez 
Valley, Huila, Colombia where I. oreas was collected at 2,900 meters 
elevation and I. scalena at 2,400 meters elevation. 

Life History and Ecology 

We have no accurate data on the length of life or the reproductive 
cycle. An adult of L. otis otis (CNHM 133263) collected January 31, 
1963 laid a cluster of eight eggs that evening. The eggs were pre- 
served in alcohol, but have not been dissected. A live nearly adult 
L. unciger taken in February, 1959 at El Valle was sexually immature 
(see fig. 5) even though lip formation had started. Many snails be- 
come sexually mature prior to lip formation or other indication of 
adulthood. Apparently this may not be the case in L. unciger. 
There are no other data available. 

Numerous young shells of L. otis orthorhinus collected in January 
and February, 1959 fell into two size classes, one of about 8 mm. in 
diameter and the other 16.5-17.5 mm. This suggests two possibil- 
ities: first, that they represent year classes, which might indicate a 
three or four-year cycle from hatching to adulthood; or second, a sea- 
sonal pattern of reproduction with two broods each year in Panama 
during the rainy seasons. The doubling in size between the two classes 
(8 to 17 mm.) would indicate roughly that adult size (35-41 mm. on 
Barro Colorado Island) could be reached in another equal period of 
time. It is equally possible that two additional periods would be re- 
quired, one to reach the actual diameter and the second to form the 
characteristic lip. While an annual, rather than a seasonal, pattern 
seems more probable, we have no data as to which is correct. The 
possible time lapse from hatching to adulthood in L. otis orthorhinus 
cannot be placed in narrower limits than l}/£ to 4 years without more 
data. We have no information concerning the length of life in other 
species. 



20 FIELDIANA: ZOOLOGY, VOLUME 50 

Ecological data are equally fragmentary. All material taken by 
myself in Panama (L. unciger and L. otis orthorhinus) was found in 
reasonably heavy forest or as dead material in recently cleared and 
burned areas. Venezuelan material (L. plicatus and L. tamsianus) 
collected by H. B. Baker (1926, pp. 16-21) was all found in heavy 
forest under logs and debris or in leaf mould near rocky ledges. Liv- 
ing L. otis orthorhinus collected in the dry season were found under 
bark on large logs (young), in leaf litter (young), under hanging bark 
on a tree trunk six to eight feet above the ground (adults), and under 
large fallen logs (adult) . For a few other species there are brief litera- 
ture comments concerning the habitat "on ground," "in leaf litter," 
etc. These are not sufficient, however, to characterize the mainland 
species as strictly terrestrial. The Puerto Rican species of camaenids 
show diverse habitats (data from van der Schalie, 1948, pp. 75-83) : 

Caracolus marginella (Gmelin) — arboreal in plains and foothills; 

Caracolus carocolla (Linn£) — arboreal in wet forest; among stones 
or decayed leaves in drier areas; 

Polydontes (Granodomus) lima (Ferussac) — arboreal on whole is- 
land, more common in lowlands; 

Polydontes (Parthena) acutangula (Burrow) — arboreal in heavy 
interior forest, aestivates in bromeliads and leaves in tree; 

Polydontes (Luquillia) luquillensis (Shuttleworth) — arboreal in 
high rain forest, aestivates in palm bracts and bromeliads; 

Zachrysia (Z.) auricoma havanensis Pilsbry — terrestrial in open, 
drier areas and in cultivated zones. 

It is obvious that the same species (C. carocolla) may be terrestrial 
under some conditions and arboreal under others. Probably the Pan- 
amanian L. otis orthorhinus is at least partly arboreal during the wet 
season. The diverse ecology shown by the Puerto Rican species sug- 
gests that quite possibly the several species of Isomeria with trans- 
Andean distributions (see pp. 207-208) may be ecologically separated. 
Certainly ecological studies of the mainland camaenids could yield 
very interesting and important data. 

Gross Anatomy 

Very little anatomical information has been recorded in the litera- 
ture. Moss and Webb (1899) figured part of the genitalia, some 
radular teeth and the jaw of Isomeria globosa (as J. subcastanea) . 
H. B. Baker (1926) dissected L. tamsianus and L. plicatus, figured 
several aspects of their anatomy and provided a general review of 



SOLEM: NEOTROPICAL LAND SNAILS 21 

their morphology. Wurtz (1955), in a supraspecific review of the 
New World camaenids, added dissections of L. clappi and L. otis 
orthorhinus and restudied Baker's material. 

Thus only five of the fifty-six species had any anatomical features 
recorded in literature. Only four species, two of them previously 
dissected and all represented by very limited material, were available 
during this study. Isomeria globosa (CNHM 70909, two specimens), 
L. diminutus (CNHM 107821, one specimen), L. unciger (CNHM 
84492, one subadult specimen), and L. otis orthorhinus (CNHM, sev- 
eral examples from Panama) were the only preserved specimens 
located. Only seven species, six Labyrinthus and one Isomeria, have 
been dissected and most of these are represented by only one example. 

In view of the very limited material, preparation of more than a 
few comparative notes, following Wurtz (1955) in recognizing sys- 
tematically important characters, was impossible. Dissections were 
limited to a review of the radula, jaw, pallial region and genitalia. 
Following the brief comments on variation in each system, a short 
discussion covers the possible systematic import of observed varia- 
tions and suggests a few hypotheses for future testing. 

Radula. — In view of the variation in radulae produced by age 
and diet, data based on single examples are not very reliable. Only 
a single good radular slide of each species was obtained. The basic 
tooth data are: 



Species 


Rows 


Tooth formula 


Isomeria globosa 


179 


50-1-50 


Labyrinthus unciger 


149 


37-1-37 


L. otis orthorhinus 


159 + 


45-1-51 


L. diminutus 


197 


44-1-44 



The asymmetrical formula of L. o. orthorhinus was caused by a major 
deformation in the central region, resulting in grossly distorted den- 
ticles. The damage was of long standing, since all current teeth rows 
showed the same deformities. 

Compared with teeth of L. tamsianus and L. plicatus (see H. B. 
Baker, 1926, pi. XIV), the cusp structure in I. globosa and L. o. ortho- 
rhinus was almost identical to that described for L. plicatus, while 
L. unciger had the structures of L. tamsianus. In L. diminutus the 
inner teeth were as in plicatus, the outer had more the shape of those 
in L. tamsianus. These are very minor variations and probably are 
of little or no phyletic significance. It was not thought worthwhile 
to illustrate the cusp structures. 



22 



FIELDIANA: ZOOLOGY, VOLUME 50 





Fig. 1. Jaws of: a, L. unciger, CNHM 84492; b, L. otis orthorhinus, CNHM 84495. 



Jaw. — Wurtz (1955, p. 109) pointed out that the jaws of most 
New World camaenids were strongly ribbed, but that in Caracolus 
and Labyrinthus the jaws were smooth. Two of the four species I 
examined had numerous low irregular longitudinal ribs on the jaw. 
While far from being as prominent as those found in Polydontes, the 
presence of incipient ribs in Labyrinthus and Isomeria does alter 
Wurtz's sharp distinction between smooth and ribbed jaws. In L. 
unciger (fig. la) the concentric striations representing the edges of the 
jaw plaits are clearly visible. There are only four or five vague longi- 
tudinal wrinkles on the central portion that continue onto the attach- 
ment membrane. The lower edge has a relatively prominent central 
cutting edge. L. otis orthorhinus (fig. lb) has a much thicker, longer, 
narrower jaw with moderately prominent longitudinal wrinkles over 
most of the surface. There is no medial protruded cutting edge and 
the concentric striations are obscured medially, although clearly vis- 
ible on the outer edges. L. diminutus has weak, evenly distributed 
longitudinal ridges with the concentric ribbing reduced. The lower 
medial cutting edge is well developed and the shape is much as in 
L. unciger. I. globosa has marked concentric striation, but only weak 
traces of longitudinal ribbing. Shape and form of the jaw are as in 
L. unciger. 



SOLEM: NEOTROPICAL LAND SNAILS 23 

Pallial region. — Apparently there is much less variation in the 
pallial regions of the New World camaenids than is found in the Old 
World species. Wurtz (1955, pp. 107-109) reviewed the patterns of 
variation found in the New World forms. Labyrinthus was shown to 
possess a long, narrow kidney that extends about one-half the length 
of the pallial region and is much longer than wide. Neither the ureter 
nor the lung surface extends apically from the kidney (K) . The peri- 
cardium (H) is much shorter than the kidney, and the secondary 
ureter (KD) is closed to the pneumostome. Dissection of the four 
available species revealed little variation and confirmed Wurtz's 
comments. 

Distortions are inevitably introduced in straightening out the pal- 
lial region for study. Measurements of organ lengths and proportions 
are thus not very accurate, but despite this still serve to indicate the 
slight variability in the mainland species. 









Ratio 




Ratio 


Length Kidney 








of 


Width 


of 


of length/ 




Pallial 


Kidney 


Kidney/ 


of 


Kidney 


Peri- Peri- 


Species 


length 


length 


Pallial 


Kidney 


L/W 


cardium cardium 


Isomeria globosa 


73 mm. 


45.5 


0.62 


2.6-2.9 


16-17 


11.7 3.9 


Labyrinthus unciger 


39 mm. 


20.0 


0.51 


1.8 


11 


5.2 3.9 


L. otis orthorhinus 


82 mm. 


50.5 


0.62 


2.1-2.6 


20-24 


10.8 4.7 


L. diminutus 


52 mm. 


27.5 


0.53 


2.1 


13 


7.2 3.8 


L. plicatus 1 


72 mm. 


38.0 


0.53 


2.9 


13 


10.0 3.8 



1 Data from Wurtz (1955, pi. 5, fig. 28). 

Possibly the larger species will be shown to have a proportionately 
longer, narrower kidney, but present data are inconclusive. There 
are no obvious structural differences between the pallial regions of 
Isomeria and Labyrinthus, although the West Indian genera (except 
Caracolus) differ markedly in kidney size and proportion. 

The structure of the pneumostomal region is quite interesting 
(fig. 3c). The hindgut (HG) opens separately (A) and a substantial 
wall of tissue separates it from the pneumono-excretory pore (KX). 
The secondary ureter (KD) is completely closed to within 1.5 mm. 
of the outer pneumostomal edge, but then is open ventrally with a 
double channel developed. The wall of the ureter on one side merges 
with an inward extension of the mantle collar that is surmounted by 
a prominent ridge and forms the upper edge of a sharply marked 
channel leading directly to the exterior. The other wall of the ureter 
is extended forward and downward at steadily decreasing height until 
it reaches the mantle collar edge. A "V"-shaped inward extension of 
the mantle collar forms a ridged barrier dividing the excretory chan- 



24 



FIELDIANA: ZOOLOGY, VOLUME 50 





Fig. 2. Pallial regions of: a, L. otis orthorhinus, CNHM 84495; b, L. diminutus, 
CNHM 107821; c, encysted nematode from L. diminutus. Scale lines equal 10 mm. 



nel into two portions, a lower, shallower groove bounded by the thin- 
walled ureter and an upper deeper groove formed by the mantle col- 
lar. The upper groove exits through the pneumostome while the 
lower groove seems to terminate within the pallial cavity. The func- 
tional significance of the lower groove is unknown. It could serve to 
channel reclaimed water into the pallial reservoir or might serve to 
bring water from the pallial reserve to flush out the waste products. 

Wurtz (1955, pp. 116, 117) reported finding encysted nematodes 
in L. clappi and L. plicatus. Three of the four species I dissected 
were free of large nematode cysts, but L. diminutus (fig. 2b) had the 
anterior pallial region literally choked with quite good-sized cysts. 
An illustration of the unidentified nematode (fig. 2c) gives an idea of 
the relatively large size. A few very small cysts were seen in the pos- 
terior pallial region of L. unciger. 



SOLEM: NEOTROPICAL LAND SNAILS 



25 



Illustrations (figs. 2, 3) have been presented of the four pallial 
regions to demonstrate the lack of variability. 

Genitalia. — Good descriptions of the genitalia of L. plicatus and 
L. tamsianus were given by H. B. Baker (1926, pp. 18, 19, 21). 
Nothing would be gained by presenting lengthy comments based on 





Fig. 3. Pallial regions of: a, I. globosa, CNHM 70909; b, L. uneiger, CNHM 
84492; c, L. uneiger, details of pneumostomal area. Scale lines equal 10 mm. 



single specimens, so descriptive comments are limited to comparative 
remarks. To provide a basis for comparison, a longer descriptive 
coverage is accorded L. diminutus. 

L. diminutus (figs. 7, 8) — ovotestis (G) of numerous digitiform, 
elongate alveoli imbedded in liver, with branched collecting ducts 
joining to hermaphroditic duct (GD). Ovotestis resembling that of 
Pleurodonte (Wurtz, 1955, pi. 1, fig. 3) much more than that of L. pli- 
catus (Wurtz, 1955, pi. 1, fig. 1). Apical portion of hermaphroditic 
duct straight, becoming strongly sinuated in one plane as it nears the 
carrefour (X). Just before reaching the carrefour, the duct is sharply 
reflexed (fig. 7c), giving the appearance of a "talon," then narrowing 
abruptly before entering the carrefour. Albumen gland (GG) very long 
and slender, probably caused by seasonal variation. Sacculated uter- 
ine oviduct (UT) and prostatic gland (DG) typical of genus. Sperma- 
theca (S) a long, thick sac bound to spermoviduct by connective 



26 



FIELDIANA: ZOOLOGY, VOLUME 50 

S 




Fig. 4. Genitalia of /. globosa, CNHM 70909: a, entire system; b, detail of 
penial complex. 

tissue, passing beyond aorta and abruptly reflexing anteriorly for a 
short distance. Vas deferens (D) a narrow tube bound into peni- 
oviducal angle, joining the much larger epiphallus (E) at the base 
of a prominent flagellum (EF) . Epiphallus a long slender tube pass- 
ing into penial sheath and reflexing apically before insertion of penial 
retractor (PR). Juncture of epiphallus and penis lies about at the 
next reflexion anteriorly (fig. 7b) . Penis (P) widest at apex, tapering 
rapidly toward atrium ( Y) . Penial retractor (PR) inserting on dia- 
phragm. Free oviduct (UV) a short, slender tube. Vagina (V) much 
thicker and quite long. Interior of terminal genitalia diversely sculp- 
tured. Lower portion of epiphallus (fig. 8a) with crowded crenulated 
ridges, becoming larger and more pustulose in the penis and occa- 
sionally surmounted by small white denticles (fig. 8b) . Vagina with 
markedly pustulose sculpturing, arranged in a criss-cross pattern, 
each pustule topped by a hooked denticle. 




27 



28 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 5. Genitalia of L. unciger, CNHM 84492. A subadult specimen. Scale 
line equals 10 mm. 



The main difference from L. tamsianus and L. plicatus lies in the 
greater length of the male genitalia and more pronounced sinuation 
of the penial complex. The small denticles in the vagina and penis 
were not found by Baker (1926) or Wurtz (1955) for L. plicatus, but 
are clearly shown by Baker (1926, pi. 13, fig. 70) for L. tamsianus. 
Baker (loc. cit.) failed to indicate the reflexion of the spermatheca, 




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29 



30 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 7. Genitalia of L. diminutus, CNHM 107821: a, entire system; b, detail 
of penial complex; c, detail of hermaphroditic duct. Scale line equals 10 mm. 



but this is properly shown by Wurtz (1955, pi. 5, fig. 25). L. clappi, 
as figured by Wurtz (1955, pi. 4, figs. 20, 21), is very similar to L. di- 
minutus, differing only in having a slightly longer penis and epiphal- 
lus. L. diminutus is thus intermediate between clappi and plicatus 
in respect to relative size of the penial complex. 

L. unciger (fig. 5) — was represented only by a juvenile example. 
Meaningful comparisons with other species are thus impossible. The 
ovotestis was well developed and extended through most of the diges- 
tive gland. In contrast, the hermaphroditic duct was a simple tube 
and the ovisperm duct not yet differentiated into uterine and pros- 



SOLEM: NEOTROPICAL LAND SNAILS 



31 



tatic portions. Albumen gland was represented by only a few cell-like 
structures extending apically from base of hermaphroditic duct. 
Penial complex was more fully developed, with vas deferens, epiphallic 
flagellum, epiphallus and penis clearly visible. The penial retractor 




Fig. 8. Interior of penial region in L. diminutus: a, penis and epiphallus; 
b, denticle form. 



was proportionately very long and thin with the penial sheath rather 
poorly developed. 

The extent to which further development would alter the propor- 
tionate size of the penial complex is unknown. At its present stage 
of development, it seems quite similar to the type found in L. plicatus. 



32 FIELDIANA: ZOOLOGY, VOLUME 50 

L. otis orthorhinus (fig. 6) — ovotestis with more ovoid alveoli than 
in L. diminutus. Hermaphroditic duct straight apically, sinuated in 
a single plane medially, then nearly straight until just before recurved 
loop (fig. 6c) . Albumen gland shorter and thicker than in L. diminutus. 
Free oviduct very slender and appears to insert into the vagina-sper- 
matheca that appears as a single organ. Vagina very thick-walled, 
spermatheca large and long. Penial complex noticeably shortened 
into a compact mass. Epiphallic flagellum proportionately very 
large. Epiphallus shortened, tightly bound to penis by muscular 
tissue (fig. 6b). Internally, flagellum with large, smooth pilasters, 
forming smooth to slightly corrugated ridges (fig. 6d) just above in- 
sertion of penial retractor. Penis proper very short and bound to 
epiphallus (fig. 6b), internally with regularly spaced pustulations sur- 
mounted by white denticles (fig. 6d) in upper portion, sculpturing 
changing to smooth ridges near juncture with vagina. Atrium with- 
out obvious sculpture. Vagina possessing corrugated ridges with a 
few denticles, which are distinctly smaller in size and with less prom- 
inent hooks than those found in the penis. The spermatheca has only 
smooth longitudinal ridges. 

Wurtz (1955, p. 117) did not find the denticles in his specimens 
of L. otis orthorhinus. Whether this was a result of different preser- 
vation or whether they are found only at certain seasons is unknown. 
Differences in the epiphallic flagellum pilaster pattern (see fig. 6d 
and compare with Wurtz, 1955, pi. 5, fig. 26) may be artifacts of 
preservation or the result of individual variations. The most strik- 
ing feature of the genitalia of L. otis orthorhinus is the shortening of 
the penial organs. The structures are identical with the other spe- 
cies, but the relative size and proportionate width are greatly changed 
from the elongated species such as L. clappi. 

Isomeria globosa (fig. 4) — ovotestis as in L. otis orthorhinus. Her- 
maphroditic duct distinctly more strongly convoluted near base, with- 
out a separate talon. Spermathecal stalk more slender, vagina shorter 
and free oviduct slightly larger in diameter. Penial complex of same 
length as in plicatus and tamsianus, epiphallus reflexed and bound in 
penial sheath, penial retractor inserting on epiphallus, penis with a 
separate flagellum (PA) . Interior of penis (fig. 4c) and penial flagel- 
lum with denticle-topped corrugated ridges. Basal portion of penis 
with smooth ridges and lacking denticles. Vagina with crowded cor- 
rugated ridges and only a few scattered denticles. The denticles 
(fig. 4d) are identical to those found in species of Labyrinthus. Base 
of vagina with the same ring of small knobs found in L. tamsianus. 



SOLEM: NEOTROPICAL LAND SNAILS 33 

The only striking peculiarity of the genitalia is the development 
of both epiphallic and penial flagellae. These are clearly shown by 
Moss and Webb (1899). Otherwise the structures do not differ mate- 
rially from those of the dissected Labyrinthus. Generally, the addition 
of a penial flagellum is not considered to be of any major systematic 
importance. The other structures are not separable from the varia- 
tions observed in the few species of Labyrinthus dissected. 

Discussion. — Only insignificant variations were observed in the 
radulae, jaws and pallial region. In the genitalia, differences are a 
matter of proportionate length of the penial organs. Of the six dis- 
sected Labyrinthus, an attempt to order the species in terms of de- 
creasing length of the penial organs would proceed in the following 
sequence — L. clappi, L. diminutus, L. plicatus, L. unciger, L. tamsi- 
anus and L. otis orthorhinus. The differences are minor between each 
adjoining pair, although large between the terminal members. The 
single dissected Isomeria shows only one quantitative difference, the 
presence of a penial appendage. In other characters, it falls within 
the range of variation shown by the dissected Labyrinthus. The ring 
of knobs at the base of the vagina is also found in L. tamsianus. 

Even casual studies of the anatomical variety shown by the West 
Indian camaenids will indicate that the anatomical uniformity of the 
mainland species is undoubtedly significant. The West Indian genera 
show great divergence, as do the Old World genera. The apparent 
lack of any anatomical diversity in South America suggests a very 
close phyletic relationship. Unquestionably, individuals of the other 
species groups of Isomeria must be dissected before any conclusions 
can be drawn, but the available anatomical evidence indicates close 
phyletic ties between the mainland camaenids. 

There seem to be no close relationships with any of the West In- 
dian genera. The "hooked" spermatheca, numerous toothed denti- 
cles in the penis and vagina, absence of a talon, long vagina, reflexed 
penis and epiphallus and absence of a penial verge are quite different 
from the West Indian taxa. Unfortunately, the data on the Old 
World genera is too fragmentary and scattered to allow comparisons 
at this time. It may be that they are more closely related to Chloritis 
(s.l.) than to any New World genus. 

The problem concerning developmental sequence of the denticles 
in the vagina and penis remains to be solved. Wurtz (1955, p. 115) 
found the denticles more numerous and more crowded in the penis of 
L. clappi than in the vagina, although well developed in both organs. 
L. diminutus had the vagina with numerous, regularly spaced denti- 



34 FIELDIANA: ZOOLOGY, VOLUME 50 

cles, but only a few were found in the penis. L. otis orthorhinus had 
many denticles in the penis, but only a few that were reduced in size 
in the vagina. /. globosa had a few scattered denticles in the vagina 
and many in the penis. 

Presumably the denticles serve a stimulatory function. It is well 
documented that in some groups of land snails an individual acts as 
a male during one coitus and a female at a succeeding time (or vice 
versa) . The denticles may develop first in one organ, degenerate and 
be reabsorbed after coitus and then grow in the other organ. The 
collection and study of mating animals will be needed to determine 
if this postulated sequential arming of the terminal genitalia does 
occur. It would explain the differences in denticle distribution found 
in dissected material. Wurtz's failure to observe the denticles in 
L. otis orthorhinus may mean that the denticles are developed only 
at certain seasons. 

At present we know nothing of the mating and reproduction of 
any camaenid. Labyrinthus and Isomer ia do have these unique den- 
ticles in the terminal genitalia, which may serve as functional equiva- 
lents of the dart appartus in the Helicidae. Comparative studies 
between species of Labyrinthus and the introduced European Helici- 
dae might yield very interesting and important developmental data. 

Classification 

The Camaenidae are a rather unspecialized family of helicoid land 
snails with a disjunctive tropical distribution. Following Wurtz 
(1955) and Zilch (1960, pp. 596-624), some 37 genera can be recog- 
nized. The Old World taxa range from Japan and Korea through 
the Philippines and Formosa to the New Guinea-Bismarck-Solomon 
arc and into Australia where a substantial radiation of desert and 
forest species has occurred, although they do not reach Tasmania. 
Abundant in Indonesia and southeast Asia, genera (Traumatophora, 
Stegodera, Grabauia) tentatively referred here are found in middle 
and south China, while several groups extend into parts of India and 
Ceylon. New World taxa are primarily found on the Greater An- 
tilles, but some Pleurodonte reach the Lesser Antilles as far south as 
Grenada and Barbadoes. Two taxa, Labyrinthus and Isomeria, have 
mainland South American distributions. 

Knowledge of the anatomy of both Old and New World species 
is too fragmentary to allow recognition of subfamilies, although Ire- 
dale (1937, 1938), in cavalier fashion, has created uncharacterized 
families for most of the Australian genera. This action should be 
ignored. Following Wurtz (1955, p. 101), the North American Am- 



SOLEM: NEOTROPICAL LAND SNAILS 35 

monitellinae and Oreohelicinae of Pilsbry are considered to be dis- 
tinct families. A few genera included as Camaeninae by Zilch (loc. 
cit.) should be eliminated. Thus Polygyratia Gray, 1847, from Brazil 
is a Streptaxid (H. B. Baker, 1925) and Solaropsis Beck, 1837, found 
over most of South America and in Eastern Costa Rica is of problem- 
atic affinities. Two Old World genera are also incorrectly classified. 
Draparnaudia Montrouzier, 1859, is an Enid (Solem, 1962, pp. 220- 
223) and Ariophantopsis Rensch, 1930, is a dyakiinine Helicarionid 
(Laidlaw and Solem, 1961, pp. 518, 519). 

The most recent review of the classification of the New World 
taxa (Wurtz, 1955) was based on a multi-character analysis of shell 
and soft anatomy features. The mainland species were all lumped 
into Labyrinthns, with two subgenera, Labyrinthus and Isomeria. 
The latter was divided into the sections Isomeria and Ambages. Fol- 
lowing an earlier historical accident, Wurtz (1955) placed Labyrinthus 
clappi in Isomeria. He separated Isomeria and Labyrinthus on the 
basis of the elongated penial region and presence of denticles in 
the penis and vagina in clappi, while these structures were absent 
in the Labyrinthus that he studied. Apparently Wurtz (1955) over- 
looked the dissection of Isomeria globosa by Moss and Webb (1899), 
since no mention was made of this paper. 

Pilsbry (1889, pp. 157-159) indicated that aenigmus and vexans 
"form a group intermediate between Isomeria and Labyrinthus," al- 
though retaining them in Isomeria. Later Gude (1912) proposed the 
generic name Ambages for these and a few species discovered subse- 
quent to Pilsbry's study. Pilsbry had not seen either species, and 
L. vexans, the type of Ambages, belongs to the L. isodon complex. 

My own dissections show that Wurtz's distinctions are untenable, 
since the denticles occur in Labyrinthus and the genitalia of L. dimi- 
nutus bridge the gap between clappi and the species dissected by 
Wurtz. The only Isomeria that has been dissected, /. globosa, does 
have a penial appendage that is absent from the studied Labyrinthus. 
This is not usually a character of generic importance, and the other 
anatomical features do not show important differences from Laby- 
rinthus. Only one-eighth of the 56 species from the mainland have 
been dissected and only one of the 28 placed in Isomeria. On the 
basis of anatomy, there is no justification for generic separation. 

Nevertheless, since the 1850's it has been recognized that the 
mainland species fall into two groupings: a lowland to medium ele- 
vation series with heavier occlusion of the aperture (Labyrinthus), 
and a high mountain series with very small to vestigial teeth in the 
aperture (Isomeria). With the exception of two species described 



36 FIELDIANA: ZOOLOGY, VOLUME 50 

below, I. inexpectata and /. minuta, the division into Labyrinthus and 
Isomeria is reasonably simple. I. minuta has the basal and lower 
palatal teeth of a Labyrinthus, but lacks a parietal lamella, while 
/. inexpectata has the shape of Isomeria, but a reduced form of Laby- 
rinthus-type dentition. 

The available anatomical evidence demonstrates a close affinity 
between the dissected species, but the combination of altitudinal and 
conchological distinctions warrants taxonomic recognition. Thus two 
genera, Labyrinthus and Isomeria, are considered here. While recog- 
nizing the differences in shell aperture and altitudinal range, the dis- 
tinction may have no phyletic significance. We have no knowledge 
of the ecological niches of Isomeria and Labyrinthus. If they prove 
to be different, then a monophyletic origin for each group would be 
possible. If their ecological positions overlap, then a polyphyletic 
origin of Isomeria from Labyrinthus (or vice versa) would seem more 
likely. In view of the diverse apertural structures of the shells, I 
would incline toward a polyphyletic origin of the two conchological 
types. Present data are totally insufficient to resolve the problems, 
and a division into two genera serves a practical purpose in recogniz- 
ing shell form and altitudinal zonation. 

Fossil Record 

No fossil camaenids have been reported from the South American 
mainland. A Jamaican Miocene fossil (Pleurodonte bowdeniana Simp- 
son, 1894) is known from two fragments (Simpson, 1894, p. 450, 
pi. 16, figs. 3-5). To a certain extent it resembles the Ecuadorean 
Isomeria globosa form kobeltiana. Both have a closed umbilicus and 
no parietal lamella, but have a prominent, posteriorly indented lower 
palatal tooth and a basal tooth. The fossil has a much larger basal 
tooth and the lower palatal tooth seems to be wider and flattened 
above. The similarities are almost certainly convergent. 

Several species from the Lower Miocene Silex beds of Tampa, 
Florida (see Dall, 1915, pp. 23, 24, pis. 1, 2, 4) have been placed in 
Pleurodonte, but with their own subgenus, Pleurodontites Pilsbry, 
1939. None shows great similarities to any of the species considered 
here. Other North American camaenid fossils are dubiously referred 
to the family or are based on unlocalized, unstratified material (Ho- 
dopoeus crassus Pilsbry and Cockerell, 1945) . 

The very fragmentary, scattered fossils provide no helpful data 
concerning the origins or distributions of the New World camaenids. 
The only fact revealed is that camaenids were formerly present in 
Florida but are now absent from North America. 



SYSTEMATIC REVIEW 

Genus LABYRINTHUS Beck, 1837 

(=Lyrostoma and Lyriostoma Swainson, 1840, Ambages Gude, 1912) 
Index Molluscorum, p. 33. 

Type species. — Helix otis Lightfoot, 1786 (= Helix labyrinthus 
"Chemnitz" Deshayes, 1838) by subsequent designation of Herr- 
mannsen (1846, p. 569). 

Range. — Northern Costa Rica south to Madre de Dios, Peru, east 
to Caracas, Venezuela and the confluence of the Rio Tapajoz and 
Amazon in Para, Brazil. Apparently absent from the Pacific slopes 
of the Andes below the Calima River basin in Valle de Cauca, Co- 
lombia, except for three records from the upper Rio Esmereldas 
drainage of Ecuador. Found from near sea level to a maximum re- 
corded altitude of 7,000 feet elevation. 

Diagnosis. — Shell small to large (diameter 12.5-60 mm.) ; de- 
pressed globose to planulate; surface sculpture of growth wrinkles or 
granulations, but never ribbed; spire nearly flat to moderately ele- 
vated; periphery rarely rounded, usually acutely angulated or protrud- 
ingly keeled ; umbilicus partly (rarely completely) closed by extension 
of basal and parietal lips; aperture strongly deflected near end of body 
whorl, partially obstructed in adult by gross expansion of lips and 
development of various denticles and lamellae; parietal lip raised and 
with reflected edge (except L. sieversi and L. clappi), basal and pala- 
tal lips thickened and strongly reflected, all lips varying from straight 
to strongly indented or sinuated; parietal wall with single short to 
long, curved to sinuated lamella (bifid in L. sharmani) that stops 
short of or variously merges with the elevated parietal lip; basal lip 
straight to sinuated, normally with one lamellar knob marking its 
outer boundary (absent in L. aenigmus), occasionally with a second 
inner knob; lower palatal lip with single crescentic lamella, hooked 
lamellar tooth, large transverse lamellar plate or "Y"-shaped bifid 
tooth with a deep indentation behind lip; upper palatal lip with weak 
lamella or triangular knob in a few species. Soft parts with typical 
camaenid structures, distinguished primarily by the elongated, sau- 

37 



38 FIELDIANA: ZOOLOGY, VOLUME 50 

sage-shaped kidney; ovoid to digitiform alveoli in the ovotestis; ab- 
sence of a talon, verge or accessory penial organs other than a 
flagellum; presence of a long, recurved spermathecal duct; smooth to 
weakly ribbed jaw; and presence of white, calcareous denticles top- 
ping the longitudinal ridges and pustules of the vagina and penis 
during at least part of the life history. 

Remarks. —Variously placed as a subgenus or section of Caracolus, 
Lucerna, Helix or Pleurodonte in the 19th century, Labyrinthus al- 
ways has been recognized as a discrete group of species confined to 
mainland America. The shell is differentiated from that of Isomeria 
in having the aperture greatly narrowed by large folds and lamellae. 

The function of the apertural folds is unknown. They do not de- 
velop until the animal stops increasing the shell diameter and forms 
the "adult" lip. Quite probably the animal is sexually mature before 
formation of the lip, although a specimen of L. unciger with partly 
formed lip had quite juvenile genitalia (fig. 5) . Pilsbry (1889, p. 159) 
and von Martens (1892, pp. 175, 176) speculated that the apertural 
folds might provide protection against snail-eating carabid beetles, 
but there is no evidence concerning possible beetle predation. On 
rare occasions the coati has been observed to eat L. otis orthorhinus 
(see p. 112), but we have no other information on the use of Labyrin- 
thus for food by animals or man. The apertural folds are very effec- 
tive in narrowing the aperture of the adult, but whether this affects 
predation is unknown. 

The presence of apertural armature is a common phenomenon in 
land snails and has evolved separately in many and diverse families. 
For example, the teeth may appear at or soon after hatching (Torna- 
tellinidae, Strobilopsidae, Endodontidae) and persist throughout life; 
in others (some Zonitidae and Enidae) there are teeth in the young, 
but none in the adults; while in many families (Pupillidae, Polygyri- 
dae, Odontostominae and Camaenidae) the teeth appear only when 
the reflected lip is formed and further increase in shell size ceases. 
Every conceivable type of variation is known and the character of 
the teeth and time of formation can vary within a family. Several 
somewhat divergent systems of nomenclature are in use for apertural 
armature. In view of the varying shape of the apertures and inde- 
pendent origins of the teeth, no attempt at standardization of termi- 
nology seems necessary or desirable. 

Previous descriptions of the apertural folds in Labyrinthus have 
been very general, complicating problems of identification and com- 
parison. For convenience in working with this group, a simple divi- 



SOLEM: NEOTROPICAL LAND SNAILS 



39 










Fig. 9. Apertural zones in Labyrinthus. 

sion of the aperture into three zones is proposed (fig. 9) . The areas 
are delineated as: 

parietal lip— portion of raised lip (or callus edge) fastened to 
penultimate whorl 
Lower Parietal Lip— portion from junction of the parietal la- 
mella to basal lip 
Upper Parietal Lip — portion from junction with parietal la- 
mella to junction with upper palatal lip 

palatal lip — portion of lip bordering body whorl from edge of 
parietal lip to outer edge of basal tooth 
Upper Palatal Lip — portion of lip between parietal wall and 

periphery of body wall 
Lower Palatal Lip — portion of lip from periphery of body whorl 
to inner edge of basal tooth 

basal lip— portion of lip from outer edge of basal tooth to junc- 
tion with parietal lip 

In forms where the parietal lamella does not reach or merge with the 
parietal lip, a division into upper and lower parietal lips is not pos- 
sible. The relative size of the two parietal lip divisions varies with 



40 FIELDIANA: ZOOLOGY, VOLUME 50 

the type and point of union of the lamella and lip. The nearly con- 
stant presence of a prominent basal tooth (except in L. aenigmus) 
and usual presence of a marked sinuosity at that point in the aperture 
make the basal tooth a convenient boundary between basal and pal- 
atal lips. 

In most groups of snails with apertural dentition (i.e., Pupillidae, 
Endodontidae, etc.) the aperture is divided into parietal, columellar, 
basal and palatal zones. The columellar region is a short zone form- 
ing the side of the umbilicus and extends from the parietal wall to the 
curve of the lip marking the baso-columellar angle. This zone is 
prominent in shells with vertical or only moderately deflected aper- 
tures. In Labyrinthus the extreme deflection of the aperture and 
tendency of the reflected lip to partly cover or dip into the umbilicus 
(see figs. 19f, 21a) has reduced the "columellar region" to the actual 
curve connecting the basal and parietal lips. This area is minimal in 
size, has no dentition and cannot be delineated from the basal and 
parietal areas. While technically it would be proper to call this curve 
the columellar region, practically this is of no importance in Labyrin- 
thus and the term "columellar area" is not utilized in this study. 

Each of the three zones shows moderately extensive variations. 
In two species with completely closed umbilicus, L. sieversi and L. 
clappi, the parietal lip is not elevated, but a very heavy callus covers 
the parietal region. In L. sp., also with a closed umbilicus, the lip 
is only moderately raised, and in L. aenigmus, where the lips cover 
most of the umbilicus, the elevation of the parietal lip is greatly re- 
duced. Most species have the parietal lip simply curved, but in those 
species in which the parietal lamella merges with the parietal lip, the 
latter may be grossly distorted with the upper portion greatly re- 
duced in prominence. The series of transitions to this are discussed 
under the L. isodon group, and reaches its highest development in 
L. magdalenensis, new species, and L. otostomus of the aenigmus com- 
plex. All species have a parietal lamella, which is the largest tooth 
in forms where it merges with the parietal lip, but is much less promi- 
nent in species where there is no such junction. 

The basal lip is occasionally straight (L. tamsianus, for example) 
and then varies to the highly sinuated condition seen in L. subpla- 
natus sipunculatus. In every species except L. aenigmus, the basal- 
palatal lip margin is marked by a high conical or lamellar tooth. In 
a few species a small to prominent second, inner basal tooth has de- 
veloped. Considerable variability is shown in the extent to which 
the parietal and basal lips parallel each other before dipping into the 



SOLEM: NEOTROPICAL LAND SNAILS 41 

umbilical opening (see figs. 30, 32, 36) and the extent to which they 
do dip into the umbilicus. 

The lower palatal region shows variously constructed teeth. The 
simplest condition, characteristic of most members of the isodon com- 
plex, is a single crescentic lamella situated at the lip edge and gener- 
ally perpendicular to the body wall at that point. From this, several 
specializations have developed. In a group characteristic of the Up- 
per Amazonian basin (L. raimondii complex) the crescentic lamella 
is supplemented by a conically triangular tooth twisted upward (see 
fig. 21) and the two are joined by a high ridge forming a "Y"-shaped 
structure. A deep posterior indention behind the lip marks the area 
of the ridge and does not require a thick calcium deposit underneath 
these teeth. Some members of the isodon complex (L. dunkeri and 
L. magdalenensis) have two crescentic lamellae on the lower palatal 
lip and in L. otostomus there are two parallel crescentic lamellae con- 
nected by a ridge with posterior indention. The other two types of 
structure are quite distinctive. In the L. unciger complex the lower 
palatal wall has a long entering ridge or lamella (whose edge may be 
smooth or fluted) surmounted posteriorly by a recessed "T"-shaped 
lamella or "fish-hook" structure (see fig. 29). In the L. otis series, 
the lower palatal lamella has become transversely oriented and varies 
from a conical ridge (L. marmatensis, fig. 36e) to a huge, spade-shaped 
crescent that almost touches the parietal lamella (L. otis, L. subpla- 
natus, figs. 30, 32). 

In the carinated or keeled species, the boundary between the up- 
per and lower palatal lips is marked outside the aperture by the 
periphery and inside only by an angle. In some species the periphery 
has a distinct groove inside the aperture and in L. subplanatus the 
peripheral groove is reflected, or even turned upward to form a spout 
(fig. 35). Comparatively few species have dentition on the upper 
palatal wall. Generally it is in the form of a small conical or crescentic 
lamella, but L. magdalenensis has a lamellar ridge and there is usually 
a deeply recessed small tooth located above the top of the lower pal- 
atal tooth in the L. otis complex. 

There is also considerable variability between species in the de- 
gree to which the aperture is deflected. Because of the sinuated lip 
and lack of any accurate way to measure the exact degree of deflec- 
tion, no attempt has been made to utilize this as a systematic char- 
acter. Generally, apertural deflection is cited as the number of 
degrees of inclination from the shell axis. In species with grossly 
deflected lips, aligning of the shell axis becomes purely guesswork. 



42 FIELDIANA: ZOOLOGY, VOLUME 50 

Variability in spire outline and point where the deflection starts make 
it impossible to utilize the sutural line as a point of standard refer- 
ence. Similarly, the sinuated nature of the lip also renders the tak- 
ing of standard measurements extremely difficult. The side views of 
the apertures and spires serve to indicate the general degree of de- 
flection and partially compensate for the lack of quantification. 

Identifications can be made primarily from the apertural arma- 
ture, although variations in size, form, degree of carination of the 
periphery, umbilical width, height and outline of spire, color pattern 
and surface sculpture are quite marked. Juvenile shells, which lack 
any trace of lip armature, can be identified only by comparison of 
their apical whorls, sculpture, color and whorl increment with adult 
specimens. 

Classification of Labyrinthus 

In view of the limited number of species dissected and the paucity 
of well localized material, it is premature to attempt anything more 
than a grouping of species. Certain relationships are obvious. L. un- 
ciger and L. creveauxianus form a natural pair; L. otis, L. subplanatus, 
L. plicatus and L. marmatensis agree in form, basic apertural charac- 
ters and show a cohesive pattern of distribution; many forms grouped 
around L. raimondii show a bewildering variety of minor variations; 
and stages in the development of merging of the parietal lip and la- 
mella can be seen in species related to L. leucodon, L. isodon, L. manu- 
eli, L. vexans and L. magdalenensis with L. otostomus an obvious 
derivative. 

Two possibly unwarranted working assumptions have been made 
in recognizing five species groups of unequal value. Small size and 
simplicity in apertural armature may have preceded large size and 
complexity in apertural armature. Immediate and obvious excep- 
tions are the small lowland L. tamsianus whose reduced apertural 
characters may have been derived from those of the larger, upland 
L. leucodon, and the reduced dentition of the Venezuelan L. plicatus 
when compared with the smaller L. subplanatus. As a general rule, 
however, comparison of probably related species shows increasing 
complexity of tooth structure with increasing size. Secondly, it is 
assumed that the apertural characters are more stable than differ- 
ences in form, size, coloration or degree of peripheral angulation. 
Groupings based on apertural structures show rather definite geo- 
graphical patterns and accommodate most of the species in fairly 
clear cut groups. 



SOLEM: NEOTROPICAL LAND SNAILS 43 

Three species groups are easily and adequately defined : group of 
L. unciger by the recessed, hooked or 'T "-shaped lower palatal la- 
mella; group of L. otis by its transversely oriented lower palatal tooth; 
and group of L. raimondii by its "Y"-shaped, bifurcated lower palatal 
tooth. The group of L. isodon is less cohesive, having simple cres- 
centic lamella (e) on the lower palatal wall, but a series of modifica- 
tions in the relationship of the parietal lamella and lip that lead 
toward the structures found in the L. aenigmus group. L. magda- 
lenensis and L. dunkeri, in particular, seem somewhat distinct from 
the rest of the L. isodon type, having several extra denticles and not 
fully conforming with the others in tooth structure. Particularly dif- 
ficult are the relationships of the two species from the Sierra Nevada 
de Santa Marta in Colombia, L. sieversi and L. clappi. Both have 
the umbilicus completely closed and the parietal lip is not elevated, 
but has been replaced by a heavy parietal callus. L. sieversi has the 
bifurcated lower palatal tooth of the L. raimondii series, and, for 
convenience, has been grouped with them, although geographically 
isolated. L. clappi has simple but grossly thickened teeth. Because 
of a general resemblance in form, size and thickening of the teeth it 
has been grouped with L. aenigmus and L. otostomus. The latter 
three probably represent separate derivations from the isodon group, 
which is tentatively considered the least specialized of the species 
groups. Available data is insufficient to suggest derivation or inter- 
relationships of the other groups. 

KEY TO THE GROUPS OF LABYRINTHUS 

1. Lower palatal wall with a deeply recessed, hooked or "T"-shaped lamella. 

Group of Labyrinthus unciger 

Lower palatal wall variously armed with teeth or lamellae situated on lip .... 2 

2. Lower palatal wall with a high conical or spade-shaped transverse lamella. 

Group of Labyrinthus otis 

Lower palatal wall with one or more crescentic lamella that are not transversely 
placed 3 

3. Two lower palatal teeth, upper triangular, lower crescentic, connected by a 

high callus, forming a "Y"-shaped structure, shell unicolored or with lighter 
peripheral zone Group of Labyrinthus raimondii 

One lower palatal tooth, or with two crescentic lower palatal teeth and either 
two basal or an upper palatal tooth present, or lower palatal teeth as above, 
but shell yellow-brown with spiral red bands 4 

4. Diameter more than 35 mm., or umbilicus completely closed, or with a triangu- 

lar ridge at lower edge of upper palatal lip forming a peripheral groove with 
parallel lower palatal teeth (fig. 23a) Group of Labyrinthus aenigmus 

Diameter less than 32 mm., umbilicus distinctly open, upper palatal tooth 
(when present) not forming edge to a peripheral groove. 

Group of Labyrinthus isodon 



44 FIELDIANA: ZOOLOGY, VOLUME 50 

Keys to the species are given for each group. Data relating to 
zoogeography, zonation and possible geographic trends follows the 
account of the species. 

REVIEW OF THE SPECIES 
Group of Labyrinthus isodon 

A series of minor and confusing differences prevent any simple 
characterization of this group. Most specimens range from 17 to 
25 mm. in maximum diameter, although individuals of L. magda- 
lenensis new species are slightly larger, L. manueli (Higgins) reaches 
a maximum of 30 mm., L. quadridentatus (Broderip) is smaller and 
the dwarf L. tamsianus (Dunker) ranges down to 12.5 mm. The um- 
bilicus is always partly open. Spire elevation and shape ranges from 
depressed globose to almost planulate. Most species are unicolored, 
but L. magdalenensis has a brilliant speckled pattern, and L. dunkeri 
spiral reddish bands on a lighter background. 

Only L. tamsianus has been dissected (H. B. Baker, 1926). Its 
anatomy shows only minor differences from that of L. plicatus (Born) . 
No soft parts were available during this study, and classification had 
to be based on differences in the apertural dentition. Most of the 
species seem to be closely related, but L. dunkeri, in particular, seems 
rather different. 

There is considerable variability in the apertural teeth. Perhaps 
the most fundamental changes are in the relationship of the parietal 
lamella and the parietal lip. Generally, a distinctly elevated parietal 
lip is formed at adulthood. Its origin may lie in the narrow pari- 
etal callus edge found in Isomeria. In most Labyrinthus this ridge 
has been altered to an extension of the body wall with a slightly to 
strongly reflected lip edge. Only in L. sieversi and L. clappi, with 
their totally closed umbilici, are the parietal walls with only a heavy 
broad callus. This may be a secondary reduction associated with 
umbilical closure. The simplest condition of the parietal lamella is a 
high, curved blade that is rather short and whose anterior end lies 
distinctly short of the raised parietal lip. This condition is typical 
of the raimondii and unciger series as well as being found in L. tripli- 
catus and L. quadridentatus (see figs. 10, 21, 28). L. sieversi has no 
elevated parietal lip, which may account for the form of the parietal 
tooth in that species as well as in L. clappi. Although L. tamsianus 
has the same short parietal lamella, it is suspected that this is a sec- 
ondary development through reduction of the type of dentition found 
in L. leucodon (see figs. 12, 13). 



SOLEM: NEOTROPICAL LAND SNAILS 45 

Actual union of the parietal lamella and lip has taken two forms. 
In one series a sinuately twisted bladelike lamella gradually is length- 
ened and finally inserts perpendicularly into the lip. The short la- 
mella in L. dunkeri (fig. 14a) is also found in the unciger group and in 
moderately lengthened form in some of the plicatus series. Finally, 
in the raimondii series, L. ellipsostomus (fig. 18) has the lamella stop 
just short of the parietal lip and in L. leprieurii the lamella inserts 
perpendicularly into the lip (fig. 16) . 

In the other series, leading from the isodon to the aenigmus com- 
plex, the parietal lamella joins or merges with the lower parietal lip at 
an extreme angle, often with the upper part of the parietal lip greatly 
reduced in prominence. Some of the plicatus series show the same 
type of joining. L. leucodon (fig. 12b) has the simplest form of union, 
with the parietal lamella beginning to decrease in height just before 
joining the lip and the upper part of the lip not appreciably reduced 
in size. In L. leucodon umbrus (fig. 12c) , the parietal lamella has not 
started to descend before the union. This type of tooth is easily de- 
rivable from the simple curved blade found in L. triplicatus. A fur- 
ther development is seen in L. isodon (fig. 14b) where the lip and 
lamella join at a distinct angle, but the upper portion of the parietal 
lip is greatly reduced in height. L. manueli (fig. 14d) and L. vexans 
(fig. 14c) are very similar, except that the merging of the lamella and 
lip is not marked by a distinct angle. A further modification occurs 
in L. magdalenensis (fig. lOd) in which the highest part of both lamella 
and lip is at the point of merging, with the upper parietal lip greatly 
reduced in size and the lower parietal lip and lamella decreasing in 
height from the point of union. The several members of the aenig- 
mus series have basically the same type of union of parietal lip and 
lamella. 

There is much less variation in the basal lip dentition. All species 
have a rounded knob or crescentic lamella marking the junction of 
the basal and lower palatal lips. Some individuals of L. manueli may 
have a second low knob, while a distinct inner tooth is found in L. iso- 
don and L. quadridentatus. L. dunkeri is unique in having a diagonal 
inner lamella (fig. 14a) for the second tooth. 

The lower palatal wall is variously armed. L. triplicatus and L. 
quadridentatus have a spade-shaped lamella that differs from the cres- 
centic lamella of L. leucodon, L. vexans, L. manueli and L. tamsi- 
anus only in being proportionately narrower. Conceivably, this is 
a forerunner of the huge transverse tooth found in the plicatus series. 
L. magdalenensis (fig. lOd) has two widely separated crescentic la- 



46 FIELDIANA: ZOOLOGY, VOLUME 50 

mellae, the upper just below the periphery. L. dunkeri has a lower 
crescentic lamella and a small upward twisted triangular tooth that 
is connected by a weakly elevated ridge with a corresponding inden- 
tation behind the lip. This is very close to the situation in the rai- 
mondii series. 

Few species have significant upper palatal dentition. A small tri- 
angular knob in L. leucodon and L. tamsianus, low diagonal lamellae 
in L. dunkeri and L. magdalenensis, and a crescentic lamella located 
on the periphery in L. isodon and slightly above in L. vexans are the 
only known examples. 

Distributional information (see fig. 57) is fragmentary and the 
scattered ranges emphasize the diverse nature of this grouping. L. 
triplicatus and L. quadridentatus are closely allied species of Western 
Panama and Costa Rica. L. vexans has been reported from Frontino 
and Canasgordas, Antioquia, Colombia. No others are known until 
L. dunkeri, L. magdalenensis and L. isodon in the Sierra de Perija 
along the Colombian -Venezuelan border. L. dunkeri has been re- 
corded from old museum collections as occurring in the Cordillera 
Occidental and Cordillera Central of Antioquia, Colombia, but these 
records may not be valid. Labyrinthus leucodon is known from Cor- 
dillera MeYida of Venezuela, and both L. leucodon and L. tamsianus 
live in the coastal ranges of Central Venezuela. They are a closely 
allied pair of species, probably equivalent to the quadridentatus-trip- 
licatus pair of Costa Rica and Panama. No species of this group have 
been reported from the Andean region of Southern Colombia. L. 
manueli is fairly widely distributed in the Ecuadorean Andes. Its 
upper known range is 2,000 feet, but it may be found at higher ele- 
vations. The lower limit is uncertain, but may be around 300 to 
1,000 feet. 

KEY TO THE LABYRINTHUS ISODON COMPLEX 

1. Parietal lamella at least slightly separated from parietal lip 2 

Parietal lamella reaching or fusing with parietal lip 6 

2. Shell unicolored or with a lighter peripheral band 3 

Shell with reddish spiral bands on a lighter background. 

Labyrinthus dunkeri (Pfeiffer, 1852) 

3. Periphery angulated, but not acutely carinated; Costa Rica and western 

Panama 4 

Periphery acutely carinated, teeth small; Venezuela. 

Labyrinthus tamsianus (Dunker, 1847) 

4. Two basal teeth, diameter less than 21 mm.; Pacific drainage 5 

One basal tooth, diameter more than 22 mm.; Atlantic drainage. 

Labyrinthus triplicatus (Martens, 1868) 



SOLEM: NEOTROPICAL LAND SNAILS 47 

5. Periphery sharply carinated, diameter less than 19 mm.; Golfo Dulce, Costa 

Rica and Comarca de Baru, Panama. 

Labyrinthus quadridentatus quadridentalus (Broderip, 1832) 

Periphery obtusely angulated, diameter more than 19 mm.; San Jos6 and 

Cartago, Costa Rica. . . .Labyrinthus quadridentatus biolleyi new subspecies 

6. One lower palatal tooth 7 

Two lower palatal teeth Labyrinthus magdalenensis new species 

7. Basal lip with one tooth present 8 

Basal lip with two teeth present 11 

8. Upper parietal lip much lower than parietal lamella 9 

Upper parietal lip equal in height to parietal lamella 10 

9. Upper palatal tooth absent; Ecuador. . . .Labyrinthus manueli Higgins, 1872 

Upper palatal tooth present; Antioquia, Colombia. 

Labyrinthus vexans (Dohrn, 1875) 

10. Umbilicus more than half covered by extension of basal and parietal lips; 

teeth large and heavy; Aragua, Venezuela. 

Labyrinthus leucodon umbrus Thompson, 1957 
Umbilicus less than half covered by extension of basal and parietal lips; teeth 
relatively small; Merida to Yaracuy, Venezuela. 

Labyrinthus leucodon leucodon (Pfeiffer, 1847) 

11. Upper palatal tooth present Labyrinthus isodon (Pfeiffer, 1853) 

Upper palatal tooth absent Labyrinthus manueli Higgins, 1872 

Labyrinthus triplicatus (von Martens, 1868). Figures 10a, 11a. 

Helix triplicate von Martens, 1868, Malak. Blatt., 15, p. 156 — Costa Rica 

(Carmiol!); Pfeiffer, 1869, Novit. Conch., 3, pp. 460-461, pi. 101, figs. 1-3; 

Pfeiffer, 1876, Monog. helic. viv., 7, p. 463. 
Helix aesopus Angas, 1878, Proc. Zool. Soc. London, 1878, pp. 72-73, pi. 5, 

figs. 11-12 — Buena Vista (?Alajuela), Costa Rica at 3,000 feet elevation 

(Boucard!); Angas, 1879, loc. cit., 1879, p. 476 — coast region and hills of 

Uren to 3,000 feet elevation (Gabb!). 
Helix (Labyrinthus) triplicate (von Martens), Pilsbry, 1889, Man. Conch. (2), 

5. pp. 165-166, pi. 41, figs. 17-19; Kobelt, 1894, Syst. Conch. Cab., I (12), 

4, pp. 629-630, pi. 180, figs. 14-15. 
Helix (Labyrinthus) triplicata var. aesopa (Angas), Pilsbry, 1889, Man. Conch. 

(2), 5, p. 166, pi. 64, figs. 27-28. 
Labyrinthus triplicatus (von Martens), von Martens, 1892, Biol. Centr. Amer., 

Moll., p. 176, pi. 10, figs. 2, a-c; Biolley, 1897, Molluscos terr. fluv. meseta 

central Costa Rica, p. 11 — Sarapiquf, Costa Rica at 500 meters elevation 

(Biolley!); von Martens, 1901, Biol. Centr. Amer., Moll., p. 628. 
Pleurodonte (Labyrinthus) triplicatus (von Martens), Pilsbry, 1894, Man. 

Conch. (2), 9, p. 95. 
Pleurodonte (Labyrinthus) aesopus (Angas), Pilsbry, 1926, Proc. Acad. Nat. 

Sci., Philadelphia, 78, p. 127 — Cahuita and Talamanca Valley, Costa Rica. 

Range. — Costa Rica, from coastal areas of Lim6n to possibly 4,500 
feet in elevation as far north as Sarapiqui, Heredia and Buenavista, 
Alajuela. Possibly in Bocas del Toro, Panama. 




Fig. 10. Apertures of: a, Labyrinthus triplicatus, Navarro, Costa Rica, CNHM 
63776; b, Labyrinthus q. quadridentatus, Coto, Costa Rica, USNM 532569; c, Laby- 
rinthus q. biolleyi, Guaitil de Pirris, Costa Rica, CM 62.5755. Holotype; d, Labyrin- 
thus magdalenensis, Tierra Nueva, Magdalena, Colombia, USNM 533878. Holotype. 
Scale line equals 10 mm. 



48 



SOLEM: NEOTROPICAL LAND SNAILS 



49 




Fig. 11. Shells of: a, Labyrinthus triplicatus, Navarro, Costa Rica, CNHM 
63776; b, Labyrinthus q. quadridentatus, Coto, Costa Rica, USNM 532569; c, Laby- 
rinthus q. biolleyi, Guaitil de Pirris, Costa Rica, CM 62.5755. Holotype; d-f, 
Labyrinthus magdalenensis, Tierra Nueva, Magdalena, Colombia, USNM 533878. 
Holotype (d, side; e, top;/, base). Scale line equals 10 mm. 



Material.— Costa Rica (ANSP 33164, CNHM 250, CNHM 127741, 
Edinburgh, MCZ 45116): LIMON— Cahuita (ANSP 140308); hills 
of Uren to 3,000 feet (Brit. Mus.) . CARTAGO— Turrialba (Jackson 
7105); Navarro (ANSP 226909, CNHM 63776); Platanillo at 600 
meters elevation (USNM 532612); Cervantes at 1,480 meters ele- 
vation (USNM 532590); Valle de Tuis at 620 meters elevation 
(USNM 190276); Tuis at 650 meters elevation (CM 62.5754, MCZ 
211181); Talamanca Valley (ANSP 140315). 



50 FIELDIANA: ZOOLOGY, VOLUME 50 

Diagnosis. — The high, slightly sinuated parietal lamella is a little 
removed from the low, straight parietal lip; basal lip with one prom- 
inent tooth; lower palatal lip with one high, slightly sinuated, spade- 
shaped, thin lamella; periphery obtusely angulated; spire moderately 
to markedly elevated; sides flat or rounded; umbilicus partly covered 
by extension of basal and parietal lips; color brown, usually with 
lighter periphery; diameter 22.3-28.7 mm., H/D ratio 0.496-0.674. 

Remarks. — The Venezuelan L. leucodon (Pfeiffer) and the Colom- 
bian L. isodon (Pfeiffer) are similar in general appearance, but can be 
easily separated. L. leucodon has the parietal lip concave with the 
tooth meeting the lip, a lower and broader lower palatal tooth, often 
an upper palatal tooth and the periphery acutely angulated. L. iso- 
don has two basal and two palatal teeth, the parietal tooth merges 
with the high lower parietal lip and the upper parietal lip is greatly 
reduced in size. The smaller L. quadridentatus (Broderip) from the 
Pacific drainage of Costa Rica is most readily differentiated by its 
two basal teeth, narrower umbilicus and distinctly smaller size. 

Form aesopus is a more elevated shell with flatter sided spire. 
Examples seem to be present in most sets of more than a few speci- 
mens and aesopus should be considered an individual variant. 

The few recorded localities are all from the Atlantic drainage in 
the coastal lowlands or from the Atlantic slopes of the Cordillera 
Central and Cordillera de Talamanca. L. triplicatus will probably 
be found in Bocas del Toro, Panama and possibly may reach southern 
Nicaragua. 

Moderate size variation is found, but only two sets of five speci- 
mens each had exact locality data. The shells from coastal Cahuita 
were much larger and more elevated than those from 650 meters ele- 
vation (see Table IV) . The difference may be exaggerated since the 
material from Tuis is only a selected part of Biolley's collection. 
Most of his material was sold in sets of one or two individuals. Quite 
possibly an altitudinal cline in respect to diameter, height and H/D 
ratio does exist, but present evidence is inadequate. 

Labyrinthus quadridentatus (Broderip, 1832) 

Very few specimens are known of this species, but they immedi- 
ately fall into two well characterized subspecies: 

L. quadridentatus quadridentatus (Broderip, 1832) —from Golfo 
Dulce, Costa Rica and Comarca de Baru, Panama is smaller (diam- 
eter 15.8-18.7 mm., mean 16.7 mm.), more sharply carinated and has 
the basal teeth small in size. 



SOLEM: NEOTROPICAL LAND SNAILS 51 

L. quadridentatus biolleyi new subspecies — from San Jose" and Car- 
tago, Costa Rica is larger (diameter 19.7-21.4 mm., mean 20.4 mm.), 
obtusely angulated at the periphery rather than carinated, and has 
very prominent basal teeth. 

They differ from other members of the L. isodon complex in hav- 
ing a simple parietal lamella, two basal teeth and only one palatal 
tooth. In appearance it is most similar to the larger L. triplicatus 
from Atlantic parts of Costa Rica and L. sieversi from Colombia. 
The latter has a closed umbilicus and a bifurcate palatal tooth, while 
the former has one basal tooth and is distinctly larger. 

Labyrinthus quadridentatus quadridentatus (Broderip, 1832). 
Figures 10b, lib. 

Carocolla quadridentata Broderip, 1832, Proc. Zool. Soc. London, 1832, p. 30 — 
"woods near Gulf of Dulce" (=Golfo Dulce, Costa Rica). 

Helix quadridentata (Broderip), Pfeiffer, 1848, Monog. helic. viv., 1, p. 399; 
Reeve, 1852, Conch. Icon., Helix, pi. 101, fig. 557; Pfeiffer, 1853, Syst. 
Conch. Cab., I (12), 2, pp. 271-272, pi. 123, figs. 9-11; Pfeiffer, 1876, 
Monog. helic. viv., 7, p. 463. 

Helix (Labyrinthus) quadridentatus (Broderip), Pilsbry, 1889, Man. Conch. (2), 
5, pp. 168-169, pi. 41, figs. 12-13. 

Labyrinthus quadridentatus (Broderip), von Martens, 1892, Biol. Centr. Amer., 
Moll., pp. 176-177— Te>raba, Costa Rica at 200-300 meters elevation 
(Pittier!); von Martens, 1901, Biol. Centr. Amer., Moll., pp. 628-629— 
Alto de Mono Tigre, near Terraba at 690-700 meters elevation in woods; 
El Pozo, Rio Grande de T6rraba; El Pital, Valley of Rio Naranjo at 200 
meters elevation; Quebrada Chenarria, Golfito and banks of Rio Coto; all 
in Puntarenas, Costa Rica (Pittier!). 

Pleurodonte (Labyrinthus) quadridentatus (Broderip), Pilsbry, 1894, Man. 
Conch. (2), 9, p. 95. 

Range. — Puntarenas, Costa Rica from the sea coast to at least 300 
meters elevation and Comarca de Baru, Panama. Possibly it will be 
found in Chiriqui Province, Panama. 

Material. — Panama: COMARCA DE BARU — Puerto Armuelles 
(ANSP 161830) ; beach near Puerto Armuelles (ANSP 226916) ; Costa 
Rica: PUNTARENAS— Coto at 10-20 meters elevation (USNM 
471784, USNM 532569) ; Quebrada de la Palma, basin of Rio Coto 
(USNM 190284). 

Diagnosis. —The high, slightly sinuated parietal lamella is dis- 
tinctly removed from the parietal lip; basal lip with two teeth, inner 
a low broad knob, outer a high, narrow lamella; lower palatal wall 
with a small, high, triangular lamella; periphery acutely carinated; 



52 FIELDIANA: ZOOLOGY, VOLUME 50 

umbilicus partly closed by extension of basal and parietal lips; spire 
strongly elevated, sides slightly rounded; color dark yellow-brown 
with lighter periphery. Diameter 15.8-18.7 mm. (mean 16.7 mm.), 
H/D ratio 0.560-0.653 (mean 0.599). 

Remarks. — The differences from subspecies biolleyi are given be- 
low in the diagnosis of the new subspecies. 

Labyrinthus quadridentatus biolleyi new subspecies. Figures 
10c, lie. 

Labyrinthus quadridentatus Biolley, 1897 (not Broderip, 1832), Moluscos terr. 
fluv. meseta central Costa Rica, p. 11 — Guatil de Pirris, Costa Rica at 
800 (?) meters (Biolley!). 

Diagnosis. — A subspecies of L. quadridentatus from the Central 
Mountains of Costa Rica, characterized by its larger size (diameter 
19.7-21.4 mm.), obtusely angulated (not acutely carinated) periph- 
ery, and stronger development of the basal lip teeth. The nominate 
subspecies is smaller (diameter 15.8-18.7 mm.), has an acutely cari- 
nated periphery, weaker lip teeth and is from Puntarenas and Co- 
marca de Baru, Panama. 

Holotype. — Carnegie Museum, Pittsburgh, number 62.5755. Guai- 
til de Pirris, Costa Rica. Collected by P. Biolley. 

Description. — Shell rather small, depressed globose, obtusely an- 
gulated at periphery, with 53^ rather tightly coiled whorls. Apex 
and spire markedly and evenly elevated, body whorl sharply deflected 
at aperture, h/d ratio 0.625. Color light yellow-brown. Whorls 
slightly rounded, suture not deeply impressed. Surface of shell with 
weak radial growth lines on spire, developing moderately prominent 
granulations on lower part of spire, becoming quite prominent on 
body whorl and base of shell. Aperture deflected sharply, inclined 
about 60° from the shell axis, somewhat constricted by teeth and 
lip. Parietal lip barely free of wall, thickened internally, very 
slightly sinuated, and entering umbilicus at columellar margin. Pari- 
etal wall with single, prominent, simple lamella free of parietal lip. 
Basal lip strongly thickened internally, reflected, with posterior in- 
dentions opposite teeth, not sinuated. Basal teeth two, inner a broad, 
rounded knob separated from the high lamellar outer basal tooth by a 
sinus that is wider than the inner tooth. Palatal lip rounded, slightly 
compressed above, with a single high twisted lamella mounted on a 
triangular base. Umbilicus narrow, about half covered by extension 
of basal and parietal lips. Diameter 19.7 mm., height 12.3 mm. 



SOLEM: NEOTROPICAL LAND SNAILS 53 

Range. — Central mountains of Costa Rica. 

Paratypes.— Costa Rica (MCZ 211236): SAN JOSE— Guaitil de 
Pirris (CM 62.5755). CARTAGO— Azahar de Cartago (ANSP 
45553, Edinburgh). ALAJUELA-SAN JOSfi border— Piedras Ne- 
gras (USNM 162838). 

Remarks. — The new subspecies is named in honor of its collector, 
the late Paul Biolley of San Jos£, Costa Rica, who was a famous 
student of Costa Rican mollusks. 

Size and shape variation in the few known specimens is summa- 
rized in Table IV. All known localities are from the Pacific slopes of 
Costa Rica and western Panama. The shell of L. quadridentatus is 
easily derivable from that of L. triplicatus by dwarfing, development 
of a second basal tooth, and more complete closing of the umbilicus. 
Further collecting is needed to establish the upper altitudinal ranges 
of both species and to see if actual intergrades occur between the 
nominate race of quadridentatus and subspecies biolleyi. 

Labyrinthus tamsianus (Dunker, 1847). Figures 12a, 13a. 

Helix tamsiana Dunker, 1847, Zeits. f. Malak., 1847, p. 80 — Puerto Cabello, 
Venezuela (Tarns!); Pfeiffer, 1848, Monog. helic. viv., 1, p. 399; Reeve, 
1852, Conch. Icon., Helix, pi. 100, fig. 556; Pfeiffer, 1854, Syst. Conch. 
Cab., I (12), 3, p. 466, pi. 156, figs. 28-29; Pfeiffer, 1876, Monog. helic. 
viv., 7, p. 463. 

Helix (Labyrinthus) tamsiana (Dunker), Martens, 1873, Ges. Naturf. Fr., Ber- 
lin, Festschr., 1873, p. 169— Chino, Yaracuy, Venezuela; Pilsbry, 1889, 
Man. Conch. (2), 5, pp. 169-170, pi. 41, figs. 5-8. 

Labyrinthus tamsianus (Pfeiffer), Jousseaume, 1889, Mem. Soc. Zool. France, 
2, p. 248 — San Esteban, Venezuela. 

Pleurodonte (Labyrinthus) tamsiana (Dunker), Pilsbry, 1894, Man. Conch. (2), 
9, p. 95; H. B. Baker, 1926, Occ. Pap. Univ. Michigan Mus. Zool., 167, 
pp. 20-21, pi. 13, figs. 68-70, pi. 14, fig. 74— San Esteban, La Quiguas and 
Bejuma, Carabobo (H. B. Baker!); Wurtz, 1955, Proc. Acad. Nat. Sci., 
Philadelphia, 108, pp. 116-118, pi. 5, fig. 30. 

Range. — Venezuela: Yaracuy and Carabobo. 

Material.— Venezuela (CNHM 100135, CNHM 100210): CARA- 
BOBO— San Estaban (ANSP 175364, ANSP 140920, CNHM 117646); 
Bejuma (ANSP 140919); 6 miles west of Puerto Cabello (USNM 
252580) ; Puerto Cabello (USNM 217642, USNM 336134, ANSP 4274, 
MCZ 74567). 

Diagnosis. — The very small parietal lamella is usually short and 
distinctly removed from the parietal lip; basal lip with single moder- 
ately prominent knob; lower palatal wall with short, simple rather 



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SOLEM: NEOTROPICAL LAND SNAILS 55 

high lamella; upper palatal wall with occasional weak tooth-like swell- 
ing on lip; periphery acutely carinated; spire markedly elevated, 
sides flat; color light yellowish brown. Surface very granulose, often 
with periostracal hairs. Diameter 12.5-17.2 mm., H/D ratio 0.536- 
0.642. 

Remarks. — The very small, simple teeth, high, flat-sided spire and 
acutely carinated periphery are diagnostic. Quite possibly this is a 
lowland derivative of L. leucodon. H. B. Baker (1926, p. 20) pre- 
sented data on size variation in lots he collected. His set from San 
Esteban had smaller shells than those taken by Swift at the same 
locality during the last century (see Table IV). No other material 
with good locality data was seen. 

Labyrinthns leucodon (Pfeiffer, 1847) 

Very little accurately localized material of this rather variable 
species was available. Eventually, several local races may be recog- 
nized. At present, two subspecies are nomenclaturally established, 
while material possibly representing a third is illustrated, but not 
described. 

L. leucodon leucodon (Pfeiffer, 1847) — from several states in North- 
ern Venezuela has the periphery acutely to obtusely angulated, the 
aperture moderately deflected and rather broad, and the teeth small 
or of average size. 

L. leucodon umbrus Thompson, 1957 — from Rancho Grande, 
Aragua has the periphery obtusely carinated, the aperture strongly 
deflected and rather narrow, and much larger teeth. 

The leucodon complex is most similar to the Costa Rican L. tripli- 
cate (von Martens), but differs most conspicuously in having a 
shorter parietal tooth that runs into the parietal lip and the lip being 
pure white rather than tinted. 

The degree of relationship to L. tamsianus (Dunker) needs inves- 
tigation. The latter may have the same ecological and geographic 
relationship that L. triplicatus and L. quadridentatus of Costa Rica 
seem to share. 

Labyrinthus leucodon leucodon (Pfeiffer, 1847). Figures 12b, d; 

13b. 

Helix leucodon Pfeiffer, 1847, Zeits. f. Malak., 4, pp. 81-82— locality unknown; 
Pfeiffer, 1848, Monog. helic. viv., 1, p. 399; Reeve, 1852, Conch. Icon., 
Helix, pi. 101, fig. 558; Pfeiffer, 1853, Syst. Conch. Cab., I (12), 2, p. 271, 
pi. 123, figs. 12-14— Tovar, Merida (Dyson!) (plate issued in 1852); Mar- 



56 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 12. Apertures of: a, Labyrinthus tamsianus, San Esteban, Venezuela, 
CNHM 117646; b, Labyrinthus l. leucodon, La Guaira, Venezuela, CNHM 126946; 

c, Labyrinthus I. umbrus, Rancho Grande, Venezuela, CNHM 64340. Paratype; 

d, Labyrinthus leucodon, undescribed subspecies, Venezuela. Zurich. Scale line 
equals 10 mm. 



tens, 1873, Ges. Naturf. Fr., Berlin, Festschr., 1873, p. 169— Caracas, 

D. F.; Chino, Yaracuy; Cumbre Mts. near Porto Cabello, Carabobo; 

Pfeiffer, 1876, Monog. helic. viv., 7, p. 463. 
Labyrinthus quadridentatus von Martens, 1860 (not Broderip, 1832), Die Heli- 

ceen, 2nd ed., p. 155 — Caracas. 
Labyrinthus leucodon (Pfeiffer), Jousseaume, 1889, Mem. Soc. Zool. France, 

2, p. 248 — Tovar, Venezuela. 
Helix (Labyrinthus) leucodon (Pfeiffer), Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 167-168, pi. 41, figs. 9-11, 14-16. 
Pleurodonte (Labyrinthus) leucodon (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 

9, p. 95; H. B. Baker, 1926, Occ. Pap. Univ. Michigan Mus. Zool., 167, 

p. 20. 

Range. — Venezuela: MeYida, Yaracuy, Carabobo, and possibly 
Districto Federal. 



SOLEM: NEOTROPICAL LAND SNAILS 



57 





Fig. 13. Shells of: a, Labyrinthus tamsianus, San Esteban, Venezuela, CNHM 
117646; b, Labyrinthus I. leucodon, La Guaira, Venezuela, CNHM 126946; c, Laby- 
rinthus I. umbrus, Rancho Grande, Venezuela, CNHM 64340. Paratype; d-e, 
Labyrinthus dunkeri, Guamilito, 1,500-2,000 feet elevation, Colombia, CNHM 
117649 (d, side; e, top). Scale line equals 10 mm. 



Material.— Venezuela (CNHM 100123, Edinburgh, Zurich, USNM 
316242, USNM 316046, USNM 316244, USNM 57287, ANSP 33160, 
ANSP 33166, ANSP 1457) ; Puerto Cabello (ANSP 4273) ; La Guiara 
(ANSP 33172, CNHM 126946); El Junquito, Caracas (USNM 
592898); Merida (SMF). "Colombia" (Zurich ex von Martens in 
1854). 

Diagnosis. — The high, simple parietal lamella starts descending 
before it runs into the parietal lip; basal lip with a broad, prominent 



58 FIELDIANA: ZOOLOGY, VOLUME 50 

knob; lower palatal tooth a prominent, crescentic lamella with strong 
lateral buttresses; upper palatal lip often with a small tuberculate 
denticle; aperture moderately deflected ; periphery acutely angulated ; 
spire normally elevated, sides flat to slightly rounded ; color brownish, 
occasionally speckled with greenish yellow. Diameter 18.9-23.5 mm., 
H/D ratio 0.395-0.590. 

Remarks. — In about one-sixth of the individuals examined the 
upper palatal tooth is absent or greatly reduced. Usually it is a small 
conical denticle, quite like those found in many Isomeria. Martens 
(1873, p. 169) noted size, shape and tooth variations in specimens 
from Caracas and Puerto Cabello. 

The differences between the subspecies in aperture deflection and 
width are obviously correlated, the greater deflection of the aperture 
having resulted in narrowing the aperture. Variation in tooth size 
probably is independently controlled. 

The single shell from Caracas and the two specimens from "Co- 
lombia" differ as much from leucodon leucodon as does leucodon um- 
brus. The smaller teeth, much less deflected aperture with wider 
mouth and obtusely carinated periphery would warrant equivalent 
nomenclatural status, but in the absence of adequate collections rec- 
ognition as a subspecies is withheld. These "subspecies" may be 
ecotypes, since the total amount of variation is not large. 

Labyrinthus leucodon umbrus Thompson, 1957. Figures 12c, 13c. 

Labyrinthus umbrus Thompson, 1957, Occ. Pap. Univ. Michigan Mus. Zool., 
591, pp. 6-7, pi. 2 — Rancho Grande, Aragua, Venezuela (Heatwole!). 

Range. — Known only from the type locality. 

Material. — Venezuela: ARAGUA — Rancho Grande (CNHM 
64340). 

Diagnosis. — The parietal lamella runs into the parietal lip at full 
height; basal lip with one very prominent knob-like tooth; lower pal- 
atal wall with high, simple, prominent lamella; upper palatal wall 
with a single, low triangular tooth; aperture very strongly deflected; lip 
strongly expanded and somewhat thickened ; periphery obtusely cari- 
nated; spire moderately elevated, slightly rounded above; color brown- 
ish with yellowish green speckling; umbilicus nearly closed by the 
extension of the basal-parietal lip. Diameter 20.5-22.5 mm. (mean 
21.2 mm.), height 9.5-11.5 mm. (mean 10.7 mm.) (data from Thomp- 
son, 1957, p. 7). 



SOLEM: NEOTROPICAL LAND SNAILS 59 

Remarks. — L. leucodon leucodon is more sharply carinated, has a 
more open umbilicus, the teeth are smaller in size, and the shell is 
less solid with a less sharply deflected aperture. 

Only nine specimens, all from Rancho Grande, are known. While 
complete intergradation with leucodon leucodon cannot be demon- 
strated with available material, the differences are so minor that I 
have no hesitation in reducing umbrus to subspecific status. Etymo- 
logically, the name "umbrus" is incorrect and should have been 
"umber," but this has no effect on nomenclatural matters. 

Labyrinthus magdalenensis new species. Figures lOd, lld-f. 

Diagnosis. — A species of Labyrinthus with the color pattern of 
Isomeria bourcieri (Pfeiffer), but the shape and complicated apertural 
dentition of the L. isodon-L. dunkeri complex. The direct joining of 
the prominent parietal lamella with the parietal lip is like L. isodon 
and L. manueli, but in possessing one basal and three palatal teeth, 
the new species is like L. dunkeri. The latter has much smaller pal- 
atal teeth, a parietal tooth free of the lip, and a color pattern of red- 
dish spiral bands on a yellowish-white background. 

Holotype. — United States National Museum number 533878 from 
Tierra Nueva, east of Fonseca, 3,700-5,000 feet elevation, Sierra 
Negra, Magdalena, Colombia. Collected by M. A. Carriker, Jr. 

Description. — Shell of average size, lenticular, acutely carinated, 
peripheral keel slightly protruding, with a little more than 4% nor- 
mally coiled whorls. Apex and spire moderately elevated, slightly 
flattened above, body whorl sharply deflected at aperture, H/D ratio 
0.405. Color translucent reddish-green with irregular, often triangu- 
lar, yellow-white opaque maculations. Lip white, aperture reddish- 
brown internally. Whorls very slightly rounded with a very faint 
supraperipheral groove. Surface of spire with infrequent radial growth 
lines and occasional granulations that become very prominent on 
body whorl and base of shell. Aperture sharply deflected, inclined 
about 55° from the shell axis, constricted by lip and teeth. Parietal 
lip free of wall, strongly sinuated, lower portion passing directly into 
a high, thin, twisted parietal lamella; upper portion curving down- 
ward, becoming perpendicular to parietal lamella. Lower part of 
parietal lip extending into umbilicus, parallel to portion of basal lip. 
Basal lip thin, sinuated, strongly reflected with a single broad ridge 
at junction with palatal lip. Palatal lip rounded below, rather flat- 
tened above periphery, broadly reflected. Palatal teeth three: lower 
high, crescent shaped, slanting diagonally backward; middle tooth 



60 FIELDIANA: ZOOLOGY, VOLUME 50 

located on elevated ridge just below periphery, lower, longer, more 
lamellate, sinuately twisted laterally; upper a narrow, prominent 
ridge slanting diagonally downward, located almost at mid-point of 
upper palatal wall. Body whorl near aperture with strong basal and 
lower palatal indentations behind lip. Umbilicus small, partially 
narrowed by extension of basal and parietal lips. Diameter 24.2 mm., 
height 9.8 mm. 

Range. — Known only from the type locality. 

Paratypes.— USNM 533878, CNHM 117645. 

Remarks.- — The distinctive color pattern, prominent parietal la- 
mella continuous with the parietal lip, and three simple palatal teeth 
immediately separate L. magdalenensis from all other Labyrinthitis. 
The similarly shaped L. dunkeri (Pfeiffer) has been found at the same 
locality, but in color and tooth structure is immediately separable. 
The more elevated, brownish, L. isodon (Pfeiffer) from Ocana, Co- 
lombia is more similar in tooth structure, but is much smaller, has 
two basal and two palatal teeth, is less carinated and unicolored. 

Size variation in the five known examples is summarized in 
Table IV. 

Labyrinthus dunkeri (Pfeiffer, 1852). Figures 13d-e, 14a. 

Helix dunkeri Pfeiffer, 1852, in Reeve's Conch. Icon., Helix, pi. 101, fig. 559 — 

Andes of Colombia; Pfeiffer, 1853, Monog. helic. viv., 3, pp. 256-257; 

Pfeiffer, 1854, Proc. Zool. Soc. London, 1852, p. 157; Pfeiffer, 1854, Syst. 

Conch. Cab., I (12), 3, p. 365, pi. 138, figs. 21-23; Pfeiffer, 1876, Ibid., 7, 

p. 463. 
Helix (Labyrinthus) dunkeri (Pfeiffer), Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 174-175, pi. 41, figs. 1-4. 
Pleurodonte (Labyrinthus) dunkeri (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 

9, p. 95. 

Range. — Colombia, from Norte de Santander to Guajira along the 
Sierra Perija, probably in Est. Zuilia, Venezuela. 

Material— Colombia: SANTANDER DEL NORTE— Guamilito 
at 1,500-2,000 feet elevation (USNM 517810). MAGDALENA— 
Tierra Nueva, east of Fonseca, Sierra Negra at 3,700-5,000 feet ele- 
vation (USNM 533877) ; Rio Maraca, Sierra Perija (ANSP 180017, 
CNHM 117648); La Palmita, trail from Loma Corredor to Ocana 
(ANSP 137825); Ocana (Zurich); western foothills of Sierra Perija 
at 200-500 meters elevation (USNM 473933, CNHM 117644); near 
Codazzi at 600 meters elevation (USNM 599518); 5-6 km. above 
Manuare (ANSP); Rio Cesar Valley (USNM 534075) ; Airoca, Sierra 



SOLEM: NEOTROPICAL LAND SNAILS 61 

Perija at 4,000-6,000 feet elevation (USNM 488784, USNM 488787). 
GUAJIRA— hills south of Carraipia (USNM 599497). ANTIO- 
QUIA— Frontino (Edinburgh); Sonson (?) (Zurich). 

Diagnosis. — The low, slightly sinuated, parietal lamella stops dis- 
tinctly short of the high parietal lip; basal lip with two well defined 
teeth, inner a low diagonal ridge slanting from inside across lip, outer 
a high crescentic lamella perpendicular to lip; lower palatal wall with 
two teeth — lower a high, crescentic lamella, upper a triangular, 
slightly hooked knob; upper palatal wall with an inconspicuous short 
lamella located just above periphery; aperture very strongly de- 
flected; periphery acutely carinated; spire flat; color yellowish-white 
with reddish-brown spiral bands bordering sutures. Diameter 18.6- 
24.9 mm., H/D ratio 0.345-0.466. 

Remarks. — The short, simple parietal lamella, two basal teeth, 
two widely separated lower palatal teeth and recessed upper palatal 
tooth are diagnostic. Recognition is most easily accomplished, how- 
ever, by the color pattern of spiral red bands on a lighter background. 
L. unciger has the same color pattern, but is much larger with only 
one basal tooth and a single deeply recessed lower palatal tooth. The 
slanted lamellar inner basal tooth of dunkeri is unique, while the small 
upper palatal tooth is only present, otherwise, in the L. otis group. 

Ascertaining the relationships of L. dunkeri is quite difficult. The 
lower palatal teeth are of the type found in the raimondii series, but 
more widely separated, while the upper palatal tooth is like those 
found in the otis series, and the color pattern is that of L. unciger. 
It would be tempting to suggest that L. dunkeri in the Sierra Perija 
and L. sieversi in the Sierra Nevada de Santa Marta are closely re- 
lated, but their only similarities are in the lower palatal teeth. Pend- 
ing study of the soft parts, L. dunkeri is placed in the isodon series, 
although it may be related to other species. 

L. dunkeri ranges from 600-6,000 feet elevation in the Sierra de 
Perija. Older, unconfirmed records from Antioquia may be the result 
of mislabeling. As often has been recorded with land shells, there is 
altitudinally correlated size variation in L. dunkeri. Comparison of 
the samples from Guamilito at 1,500-2,000 feet elevation (USNM 
517810) and Tierra Nueva at 3,700-5,000 feet elevation (USNM 
533877) show that specimens from the higher elevation are signifi- 
cantly larger, but not significantly different in proportions. In respect 
to height (n=10, t= 5.815) and diameter (t= 6.933) the probability 
level is much less than 0.001, while for the differences in proportion 
(H/D ratio, t= 1.119) the probability level lies between 0.2 and 0.3 



62 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 14. Apertures of: a, Labyrinthus dunkeri, Guamilito, 1,500-2,000 feet 
elevation, Colombia, CNHM 117649; b, Labyrinthus isodon, Ocana, Colombia, 
ANSP 104823; c, Labyrinthus vexans, Frontino, Colombia. Zurich, ex Mousson. 
Probably a paratype; d, Labyrinthus manueli, Mera, Ecuador, CNHM 126947. 
Scale line equals 10 mm. 

that they could have been drawn from the same population. Such 
size differences and "dwarfing effects" have most frequently been 
shown to correlate with rainfall and moisture factors and the appar- 
ent "altitude correlation" has been subsequently demonstrated to 
reflect the common phenomenon of increase in rainfall with increase 
of elevation on montane slopes. Presumably such a moisture factor 
operates in size variation in L. dunkeri, but no ecological data are 
available for the reported localities. 

L. magdalenensis was also collected at Tierra Nueva, but the eco- 
logical relationships or differences are unknown. 



Labyrinthus isodon (Pfeiffer, 1853). Figures 14b, 15a. 

Helix isodon Pfeiffer, 1853, in Reeve's Conch. Icon., Helix, pi. 149, fig. 965 — 
Western Colombia; Pfeiffer, 1853, Monog. helic. viv., 3, p. 257; Pfeiffer, 
1854, Proc. Zool. Soc. London, 1852, pp. 84-85; Pfeiffer, 1854, Syst. Conch. 
Cab., I (12), 3, p. 490, pi. 160, figs. 19-21; Pfeiffer, 1876, Monog. helic. viv., 
7, p. 463. 



SOLEM: NEOTROPICAL LAND SNAILS 



63 



Helix (Labyrinthus) isodon Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, p. 175, 

pi. 64, figs. 19-21. 
Pleurodonte (Labyrinthus) isodon (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 

9, p. 95. 

Range. — Ocana, Norte de Santander, Colombia is the only re- 
corded locality. 

Material.— Colombia: NORTE DE SANTANDER— Ocana 
(ANSP 104823, CNHM 127742, Zurich, Edinburgh); ? Mt. Lucero 
(Zurich). 

Diagnosis. — The high sinuately twisted parietal lamella attaches 
at full height to the lower parietal lip, but forms a distinct angle at 
the junction, while the upper part of the parietal lip is greatly reduced 
in height; basal lip with two prominent, crescentic teeth, the inner 
smaller; lower palatal wall with two subequal teeth, upper a small 
triangular lamella twisted upward, lower one a much higher cres- 





FlG. 15. Shells of: a, Labyrinthus isodon, Ocana, Colombia, ANSP 104823; 
b, Labyrinthus vexans, Frontino, Colombia. Zurich, ex Mousson. Probably a 
paratype; c, Labyrinthus manueli, Mera, Ecuador, CNHM 126947; d, Labyrinthus 
sieversi, San Miguel, Sierra Nevada de Santa Marta, Colombia, ANSP 140048. 
Scale line equals 10 mm. 







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SOLEM: NEOTROPICAL LAND SNAILS 65 

centic blade; aperture moderately deflected; periphery acutely to 
obtusely angulated; spire markedly and evenly elevated, sides flat to 
gently rounded; color dark yellow brown. Diameter 16.0-21.4 mm., 
H/D ratio 0.560-0.651. 

Remarks. —The two palatal teeth and less perfect junction of the 
parietal lamella with the lower parietal lip easily separate this spe- 
cies from L. manueli (Higgins) from Ecuador, which seems to be the 
nearest relative. Only the five specimens labeled "Ocana" had rec- 
ognizable data. The single shell from the Mousson collection labeled 
"Mt. Lucero" was collected by Stame and received from Landolt in 
1875. The location of "Mt. Lucero" is unknown. 

Labyrinthus vexans (Dohrn, 1875). Figures 14c, 15b. 

Helix {Isomeria) vexans Dohrn, 1875, Nachr. d. Malak. Gesell., 7, p. 57 — 

Canasgordas, Antioquia, Colombia; Dohrn, 1875, Jahr. deutsch. Malak. 

Gesell., 2, pp. 294-295, pi. 10, figs. 3-4; Pfeiffer, 1876, Monog. helic. viv., 

7, p. 591; Dohrn, 1886, Syst. Conch. Cab., I (12), 4, p. 626, pi. 180, figs. 

3-4; Pilsbry, 1889, Man. Conch. (2), 5, pp. 158-159, pi. 42, figs. 38-39, 

pi. 44, figs. 5-6. 
Pleurodonte (Isomeria) vexans (Dohrn), Pilsbry, 1894, Man. Conch. (2), 9, 

p. 94. 
Labyrinthus (Ambages) vexans (Dohrn), Zilch, 1960, Handb. Palaozool. (6), 2, 

(4), p. 603, fig. 2117 — Canas Gordas, Colombia (lectotype). 

Range. — Known only from the type collection. 

Material.— "New Granada" (ANSP 63598, MCZ 79494) . Colom- 
bia: ANTIOQUIA— Frontino (Zurich). 

Diagnosis. — The parietal lamella is high and continuous with the 
lower portion of the parietal lip, while the upper parietal lip is greatly 
reduced and inserts almost perpendicularly into the lower portion; 
basal lip nearly straight with one very prominent crescentic lamella 
and a small inner knob or diagonal lamella; lower palatal lip with a 
high, thin lamella; upper palatal lip with a lower high lamella; um- 
bilicus partly closed by parietal and basal lips; periphery obtusely 
angulated. Diameter 26.0-28.2 mm. (mean 27.1 mm.), H/D ratio 
0.503-0.542 (mean 0.526). 

Remarks. — The teeth are very similar to those found in L. isodon, 
except for the lack of an angle at the junction of the parietal lamella 
and lip. In form and shape, vexans is quite similar to L. manueli, 
but differs in being less carinated and having an upper palatal tooth. 
No recent collections of this species are known. 



66 FIELDIANA: ZOOLOGY, VOLUME 50 

Labyrinthus manueli Higgins, 1872. Figures 14d, 15c. 

Helix quadridentata Hidalgo, 1870 (not Broderip, 1832), Viaje al Pacifico, Moll., 

pp. 16-17, pi. 1, figs. 8-9— Napo, Ecuador. 
Labyrinthus manueli Higgins, 1872, Proc. Zool. Soc. London, 1872, p. 686, 

pi. 56, figs. 5, a — Macas, Ecuador. 
Helix manoeli (sic) (Higgins), Pfeiffer, 1876, Monog. helic. viv., 7, p. 462. 
Labyrinthus manceli (sic) (Higgins), Miller, 1878, Malak. Blatt., 25, p. 167. 
Labyrinthus manueli Higgins, Cousin, 1887, Bull. Soc. Zool. France, 12, p. 64 — 

Napo, Ecuador. 
Labyrinthus quadridentata Hidalgo (not Broderip, 1832), Miller, 1878, Malak. 

Blatt., 25, p. 167; Cousin, 1887, Bull. Soc. Zool. France, 12, pp. 64-65. 
Helix (Labyrinthus) manueli (Higgins), Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 166-167, pi. 41, figs. 20-21, pi. 42, figs. 27-28, pi. 55, figs. 15-16; Rei- 

bisch, 1896, Abhl. Naturwiss. Gesell., Isis, Dresden, 1896, p. 55 — Mapoto, 

Pastaza Valley, Ecuador. 
Pleurodonte (Labyrinthus) manueli (Higgins), Pilsbry, 1894, Man. Conch. (2), 

9, p. 96. 

Range. — Upper Amazonian slopes of Ecuador with one record 
from the headwaters of a tributary of the Rio Guayas on the Pacific 
slopes. 

Material— Ecuador (ANSP 33165, ANSP 107809, Zurich, Edin- 
burgh) : Santo Domingo de los Colorados (Jackson 10159) ; Abitagua, 
Pastaza Valley (Jackson 5714, MCZ 90941) ; Puyo (Jackson 6235) ; 
Mera (Jackson 7834, CNHM 126947) ; Antisana (Jackson 10145) ; 
Napo (MCZ 156694); Guama Hill, 2,000 feet elevation, Banos, Tun- 
gurahua (MCZ 65725) ; Mendez, Upper Paute River (USNM 426536). 

Diagnosis. — The single, high, curved parietal tooth is continuous 
with the lower parietal lip; upper parietal lip much reduced in size, 
inserting perpendicularly onto lamella; basal lip nearly straight, with 
1-2 low knobs; inner basal knob moderately prominent, low and 
rounded, outer basal knob varying from absent to a low swelling or 
as large as inner basal tooth; lower palatal wall with single crescentic 
lamella, buttressed laterally; spire moderately and evenly elevated; 
color brownish, with or without a lighter peripheral band. Diameter 
21.6-30.1 mm. (mean 25.9 mm.), H/D ratio 0.465-0.560 (mean 0.502). 

Remarks. — L. isodon differs from L. manueli in having an imper- 
fect union of the parietal lamella and lip, two palatal teeth and two 
strongly developed basal teeth. Other Labyrinthus are easily sep- 
arated by differences in tooth number or in having the parietal tooth 
differently constructed. The presence or absence of the second basal 
tooth is about equally frequent. No set contained more than four 
specimens, so that there is no data indicating if this variation is geo- 



SOLEM: NEOTROPICAL LAND SNAILS 67 

graphically correlated. Specimens from Abitagua, Puyo and Mera 
are several millimeters larger than those from Santo Domingo de los 
Colorados, M^ndez and Antisana, but the numbers involved (4, 3, 4, 4, 
1, and 2, respectively) are too small for meaningful statistical analysis. 

Group of Labyrinthus raimondii 

Several species described from the Upper Amazonian basin agree 
in having one simple parietal tooth, a single basal knob and a mark- 
edly bifurcated lower palatal tooth. Occasionally there is a thread- 
like trace on the upper palatal lip that follows the line of the periphery. 
Sometimes this trace is represented by a lighter color zone. Authen- 
ticated records range from the Upper Caqueta drainage of Colombia 
south to the Madre de Dios drainage of southeastern Peru and east 
into Para, Brazil. Most of the specimens come from the foothills of 
the mountains in Caqueta and Amazonas, Colombia; Ecuador; and 
Loreto, Peru; but a few are known from San Martin, Libertad, Junin, 
Cusco and Madre de Dios, Peru. There are two valid records from 
Para, Brazil, and a few records from Amazonas. A species from the 
Sierra Nevada de Santa Marta, Magdalena, Colombia is also classi- 
fied here. 

Much of this area has high rainfall, but conditions vary from ex- 
treme seasonal patterns to almost continual downpour. Eventually 
the large size variation in the shells may be correlated with moisture 
conditions. Presently this is impossible. There is a confusing mass 
of minor changes in size, degree of carination, openness of umbilicus, 
color of the lip, size and shape of the parietal lamella and degree of 
deflection of the aperture. Several specific names are available, but 
species units cannot be recognized. The shells show insufficient char- 
acters to create other than arbitrary, artificial divisions. One or two 
forms seem to be moderately well characterized, but their mosaic dis- 
tribution with related morphs complicates intelligent treatment of 
the complex. The meaning of observed variation cannot be evalu- 
ated because only a few sets contain more than three specimens, 
ecologic information is totally absent, there have never been two 
collections from the same locality at different times, and soft parts 
of only one form are available. In view of the extreme variability 
and uncertain classification, no attempt has been made to diagnose 
most of the forms. 

Particular difficulty is experienced in separating the several rela- 
tively small species. The dividing line is especially tenuous between 
L. ellipsostomus and L. diminutus since individuals were seen that 



68 FIELDIANA: ZOOLOGY, VOLUME 50 

could be classified as large, less sharply carinated L. ellipsostomus, or 
small, thin-shelled, rather sharply carinated L. diminutus or L. promts. 
Unfortunately, most such material was from older collections and 
lacked accurate locality data. It is quite possible that ellipsostomus 
will be shown to be a form of the Amazonian flood-plain regions of 
Brazil with diminutus and pronus representing, respectively, south- 
ern and northern derivatives of only subspecific status. The rather 
well-marked L. leprieurii differs in having the sinuated parietal la- 
mella inserting perpendicularly into the parietal lip, while in only a 
few isolated examples of the other species does the parietal lamella 
even slightly touch the parietal lip. L. sieversi from the Sierra Ne- 
vada de Santa Marta, Magdalena, Colombia is geographically iso- 
lated and differs in having two distinct basal teeth, rounded periphery 
and a closed umbilicus. It is classified with the raimondii series since 
it has the same lower palatal dentition, but stands quite isolated in 
other characters. L. sieversi could be related to L. clappi or else a 
very specialized member of the L. isodon complex. L. sp. is very sim- 
ilar to L. sieversi, but has a less completely closed umbilicus and only 
one basal tooth. 

The larger species are more easily distinguished. L. tarapotoensis 
and its subspecies baeri have a white lip and obtusely angulated pe- 
riphery; L. raimondii has a brown lip and acutely angulated periphery. 
L. furcillatus a white to brown lip with the arms of the lower palatal 
tooth widely separated and an obtusely angulated periphery; L. bi- 
furcatus is a much higher shell with very narrow umbilicus, obtusely 
angulated periphery and white or brown lip. 

It must be emphasized that these divisions are arbitrary and may 
not accurately reflect relationships. L. leprieurii, L. pronus and L. 
tarapotoensis baeri are reported from the same locality, Doma Santa 
Clara, 6° 55' S, Ucayali River Valley, Loreto, Peru, based on a few 
dead collected shells in the USNM. Presently available specimens 
can be segregated into the nomenclatural units outlined below, but 
provision of adequate materials for study could radically alter the 
proposed classification. Since the taxa are so similar in appearance, 
use of the key will be greatly facilitated by reference to the figures. 

To some extent, the species show geographic isolation (fig. 58), 
although there are no recorded localities for L. sp., L. bifurcatus or 
L. furcillatus. L. sieversi is isolated in Magdalena, Colombia, but the 
remaining species are found in the Amazonian basin from the Rio 
Tapaj6z in Para, Brazil to Caqueta, Colombia and south to Madre 
de Dios, Peru. Most records are from the Amazonian foothill region 



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70 FIELDIANA: ZOOLOGY, VOLUME 50 

of the Andes. L. ellipsostomus from the Rio Solimoes and Santa Fe 
de Bogota may range from Amazonas, Brazil into the upper Orinoco 
drainage of Colombia, but the enigmatic "Santa Fe de Bogota" gives 
no information as to the northern limit of its range. L. pronus from 
Loreto and San Martin (Ucayali and Huallaga drainages) and L. 
diminutus from Cusco, Madre de Dios and Junin in Peru, plus the 
Jurua River in Amazonas, Brazil could be (as mentioned above) de- 
rivatives of L. ellipsostomus. L. leprieurii from Loreto and San Mar- 
tin, Peru has been collected with L. pronus and may also have been 
derived from L. ellipsostomus. The larger white-lipped L. tarapoto- 
ensis ranges from 975-5,000 feet in scattered areas of northern and 
eastern Peru, while the larger subspecies baeri has been reported only 
from San Martin and Loreto. The widest ranging species is L. rai- 
mondii, recorded from Caqueta, Colombia south to southern Loreto, 
Peru and east to the confluence of the Rio Tapajoz and Amazon in 
Para, Brazil. Particularly puzzling in the latter species is the appear- 
ance of a dwarf variety (see Table VI) with narrower umbilicus, higher 
spire and much smaller size, but otherwise very similar to raimondii. 
This peculiar form may represent an unnamed species, but in view 
of the variability and uncertain classification, nomenclatural recog- 
nition has been withheld. 

KEY TO THE LABYRINTHUS RAIMONDII COMPLEX 

1. Umbilicus completely closed 2 

Umbilicus at least slightly open 3 

2. Basal lip with two teeth; Magdalena, Colombia. 

Labyrinthus sieversi (von Martens, 1889) 
Basal lip with one tooth; probably Ecuador or Peru Labyrinthus sp. 

3. Parietal lamella free of parietal lip or just reaching lip 4 

Parietal lamella merging perpendicularly with parietal lip at full height (fig. 16b) 

Labyrinthus leprieurii (Petit, 1840) 

4. Periphery obtusely angulated or rounded 5 

Periphery acutely angulated, often with protruding keel 8 

5. Umbilicus moderately open, H/D ratio less than 0.500 6 

Umbilicus slightly open, H/D ratio more than 0.500 

Labyrinthus bifurcatus (Deshayes, 1838) 

6. Arms of lower palatal tooth close together (fig. 21a), lips white 7 

Arms of lower palatal tooth set far apart (fig. 21e), lips white or brown. 

Labyrinthus furcillatus (Hupe, 1853) 

7. Diameter 38-44 mm., parietal lamella often meeting lip. 

Labyrinthus tarapotoensis baeri Dautzenberg, 1902 
Diameter 30-38 mm., parietal lamella not meeting lip. 

Labyrinthus t. tarapotoensis (Moricand, 1858) 

8. Diameter usually much less than 30 mm 9 

Diameter usually much more than 31 mm. 

Labyrinthus raimondii (Philippi, 1867) 



SOLEM: NEOTROPICAL LAND SNAILS 71 

9. Lip white 10 

Lip brown Labyrinthus raimondii (Philippi, 1867) dwarf form 

10. Periphery acutely angulated, but not keeled, shell thick 11 

Periphery with knife-edge keel; shell thin. 

Labyrinthus ellipsostomus (Pfeiffer, 1854) 

11. Spire flat or only slightly elevated; Loreto and San Martfn, Peru. 

Labyrinthus pronus Pilsbry, 1932 

Spire normally elevated; Junin, Cusco and Madre de Dios, Peru; Amazonas, 

Brazil Labyrinthus diminutus Gude, 1903 

Labyrinthus sieversi (von Martens, 1889). Figures 15d, 16a. 

Helix sieversi von Martens, 1889, Conch. Mitteil., 3, pp. 7-8, pi. 41, figs. 5-6 — 

below Oblo at 100-300 meters elevation, Sierra Nevada de Santa Marta, 

Magdalena, Colombia (Sievers!). 
Caracolus (Labyrinthus) sieversi (von Martens), Pilsbry, 1892, Man. Conch. 

(2), 8, pp. 263-264. 
Pleurodonte (Labyrinthus) sieversi (von Martens), Pilsbry, 1894, op. cit. (2), 9, 

p. 95, pi. 22, figs. 7-8. 

Range. — Colombia: Sierra Nevada de Santa Marta, Magdalena, 
from at least 300-5,500 feet elevation. 

Material. — Colombia: MAGDALENA — Los Gorros, old trail from 
Fonseca to Riohacha, northeast spur of Sierra Nevada de Santa Marta 
at 2,500 feet elevation (USNM 488812) ; San Miguel, Sierra Nevada 
de Santa Marta at 5,500 feet elevation (ANSP 140048). 

Diagnosis. — The high, slightly sinuated parietal lamella does not 
reach the edge of the thick parietal callus; parietal lip ap pressed to 
wall; umbilicus closed by basal lip and parietal callus; basal lip with 
two prominent teeth; two lower palatal teeth, upper a triangular 
somewhat hooklike knob slanting upward, lower a high diagonally 
slanted lamella; aperture strongly deflected; periphery rounded, very 
faint trace of angulation; spire high, slightly rounded; color brown- 
ish. Diameter 17.4-19.0 mm., H/D ratio 0.650-0.702. 

Remarks. — The completely closed umbilicus, two basal teeth, and 
parietal lip appressed to the penultimate whorl immediately separate 
L. sieversi from other members of the L. raimondii complex. It some- 
what resembles L. clappi Pilsbry, but the form of the teeth is much 
nearer to that found in L. ellipsostomus and L. leprieurii. Only three 
specimens were seen during this study. 

Labyrinthus species. Figure 19a-c. 

Helix bifurcata var. Pfeiffer, 1852, Syst. Conch. Cab., I (12), 2, p. 207, pi. 105, 
figs. 2-4; Pfeiffer, 1859, Monog. helic. viv., 4, p. 305; Pilsbry, 1889, Man. 
Conch. (2), 5, pp. 170-171, pi. 42, figs. 29-31, pi. 64, figs. 24-25. 



72 



FIELDIANA: ZOOLOGY, VOLUME 50 



Range. — Unknown . 

Material— Peru: SAN MARTIN— Moyobamba (Edinburgh, 
CNHM 132548). 




Fig. 16. Apertures of: a, Labyrinthus sieversi, San Miguel, Sierra Nevada de 
Santa Marta, Colombia, ANSP 140048; b, Labyrinthus leprieurii, "French Gui- 
ana," CNHM 40763; c, Labyrinthus leprieurii, "Guyana." Zurich, ex Petit. Para- 
type; d, Labyrinthus leprieurii, form auriculina, Meobamba, Peru, CNHM 40775. 
Scale line equals 10 mm. 



Remarks. — In this species the umbilicus has become completely 
closed and the spire is markedly elevated and rounded above. First 
recognized and figured by Pfeiffer (1852), the only locality record 
is that cited above. While it may be correct, I suspect that it was 
added to the specimens based on the recorded locality for L. bifur- 
catus in Pfeiffer's Monog. helic. viv. Although unquestionably dis- 
tinct from all described species, nomenclatural recognition should be 
withheld until adequately localized material is available. L. sieversi 
from Magdalena, Colombia immediately differs in having two basal 
teeth, but is otherwise similar. 



SOLEM: NEOTROPICAL LAND SNAILS 



73 




Fig. 17. Shells of: a, Labyrinthus leprieurii, "French Guiana," CNHM 40763; 
b, Labyrinthus leprieurii, "Guyana." Zurich, ex Petit. Paratype; c, Labyrinthus 
leprieurii, form auriculina, Meobamba, Peru, CNHM 40775; d, Labyrinthus lepri- 
eurii, form auriculina, "Guyana." Zurich; e, Labyrinthus ellipsostomus, Bogota, 
Colombia, ANSP 109259. Scale line equals 10 mm. 



Labyrinthus ellipsostomus (Pfeiffer, 1854). Figures 17e, 18. 

Helix ellipsostoma Pfeiffer, 1854, in Reeve's Conch. Icon., Helix, pi. 198, 

fig. 1389— Santa Fe de Bogota, Colombia; Pfeiffer, 1855, Proc. Zool. Soc. 

London, 1854, p. 288; Pfeiffer, 1859, Monog. helic. viv., 4, p. 307; Pfeiffer, 

1876, Ibid., 7, p. 463. 
Helix yalesii Pfeiffer, 1855, Proc. Zool. Soc. London, 1855, pp. 92-93, pi. 31, 

figs. 13-14 — Solimoes River, Brazil; Pfeiffer, 1859, Monog. helic. viv., 4, 

p. 306; Pfeiffer, 1876, Ibid., 7, p. 462. 
Helix (Pleurodonte) yatesii Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, p. 173, 

pi. 42, figs. 34-37. 

Helix (Pleurodonte) ellipsostoma Pfeiffer, Pilsbry, 1889, Ibid. (2), 5, pp. 173- 
174, pi. 41, fig. 22. 

Pleurodonte (Labyrinthus) yatesi (Pfeiffer), Pilsbry, 1894, Ibid. (2), 9, p. 95; 
von Ihering, 1905, Rev. Museu Paulista, 6, pp. 456-457 — Regiao de San 



74 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 18. Aperture of: Labyrinthus ellipsostomus, Bogota, Colombia, ANSP 
109259. Scale line equals 10 mm. 



Felipe, Rio Jurua, Est. Amazonas, Brazil (Garbe!); Lange de Morretes, 
1949, Arq. Museu Paranaense, 7, p. 163. 
Pleurodonte (Labyrinthus) ellipsostoma (Pfeiffer), Pilsbry, 1894, Man. Conch. 
(2), 9, p. 95. 

Range. — Probably upper Orinoco drainage of Colombia and the 
upper Amazonian basin of Brazil and Peru. 

Material— Brazil (USNM 307448, ANSP 1458, ANSP 33171, 
ZMA) ; AMAZONAS— Rio Solimoes (Edinburgh, CNHM 127744, ex 
Hugh Cuming, probably paratypes) ; Rio Jurua (Brit. Mus. 1903.4. 
14.4). Peru: SAN MARTIN— Moyobamba (ANSP 33159, SMF 
26379); LORETO— Ucayali (MCZ 74570); ?banks of the Rio Ma- 
rafi6n (Marignanufer in Zurich collection). Colombia (ZMA) : CUN- 
DINAMARCA— (Santa Fe de) Bogota (ANSP 109259, Edinburgh, 
CNHM 127743). 

Diagnosis. — The high, thin, sinuately twisted parietal lamella 
stops short of the raised parietal lip; basal lip with a prominent, cres- 
centic lamellar ridge; lower palatal lip only moderately indented 
with two teeth joined by an elevated ridge; lower tooth a thin cres- 
centic, blade-like lamella pointed perpendicularly toward parietal 
wall; upper lower palatal tooth a narrow, curved hook-like structure 
pointing toward upper palatal margin; aperture strongly deflected; 
umbilicus narrow to moderately open; periphery acutely angulated or 



SOLEM: NEOTROPICAL LAND SNAILS 75 

keeled; spire moderately elevated, sides flat to slightly rounded; color 
yellow brown. Diameter 17.3-24.0 mm., H/D ratio 0.432-0.541. 

Remarks. — The original descriptions indicated that yatesi (diame- 
ter 24 mm.) was distinctly larger than ellipsostomus (diameter 20 mm.). 
Material seen during this study was exactly opposite, the ellipsostomus 
(see Table VII) being larger than the probable paratypes of yatesi. 
The tooth structure of the two sets is identical and no hesitation is felt 
in uniting the species. Unfortunately, all known material dates from 
collections in the last century and, except for the record by von Iher- 
ing (1905), no exact locality is known. 

The nearest relatives are apparently L. leprieurii (Petit) from 
French Guiana(?) and Peru, in which the parietal lamella is joined 
to the parietal lip and the periphery is much less acutely angulated; 
and the thicker shelled, less acutely keeled L. diminutus and L. pro- 
mts. Both L. dunkeri (Pfeiffer) and L. isodon (Pfeiffer) have similar 
shape and form, but are easily distinguished by having two basal 
teeth. 

Size range was moderate (diameter 17.3-24.0 mm., mean 19.4 
mm.) and the degree of elevation average (H/D ratio 0.432-0.541, 
mean 0.481). The umbilicus varied from very narrow to slightly 
open (D/U ratio 10.3-24.5, mean 16). 

Labyrinthus diminutus Gude, 1903. Figures 19d-f, 21a. 

Labyrinthus baeri Dautz. var. diminuta Gude, 1903, Proc. Malac. Soc. London, 
5 (4), p. 262, pi. 7, figs. 1-4 — Perene, Dept. Junfn at 900 meters elevation 
and Sagarmo at 1,000 meters elevation, Peru (Rosenberg!). 

Pleurodonte (Labyrinthus) Da Costiana Preston, 1907, Ann. Mag. Nat. Hist. 
(7), 20, pp. 490-491, fig. 3— Chanchamayo, Junln, Peru. 

Pleurodonte (Labyrinthus) dacostiana Preston, Haas, 1952, Fieldiana: Zool., 
34 (9), p. 117 — Hacienda Cadena, Dist. Marcapata, Prov. Quispicanchi, 
Dept. Cusco, Peru at 1,000 meters elevation (Kalinowski!). 

Range. — Peru, Junin in the Apurimac drainage; Cusco and Madre 
de Dios in the drainage of the Madre de Dios; Rio Jurua in Brazil. 

Material. — Peru (Edinburgh) : JUNIN — Perene - at 900 meters 
(Edinburgh, types of diminuta Gude) ; Sagarmo (?) at 1,000 meters ele- 
vation (CNHM 40770, paratype of diminuta Gude, 1903); Chancha- 
mayo (USNM 202504, holotype of dacostiana Preston, ANSP 45551, 
paratype, ANSP 45552); Chanchamayo Valley at 1,100 meters 
(USNM 601829) ; Chanchamayo Valley at 1,300 meters (SMF 141093) . 
CUSCO— Hacienda Cadena, Dist. Marcapata, Prov. Quispicanchi 
(CNHM 28152); Rio Paucartambo, Rio Perene" (CNHM 107821). 



76 



FIELDIANA: ZOOLOGY, VOLUME 50 




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Fig. 19. Shells of: a-c, Labyrinthus sp., Meobamba, San Martin, Peru, CNHM 
132548 (a, top; b, base; c, side); d-f, Labyrinthus diminutus, Perene, Junin, Peru. 
Edinburgh. Lectotype (d, side; e, top;/, base). Scale lines equal 10 mm. 



MADRE DE DIOS-Boca Inambari, near Manu (CNHM 53634). 
Brazil: AMAZONAS— Rio Jurua (USNM 171453). 

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than the types of diminutus, but agree perfectly in the apertural den- 
tition. There seems to be very little difference between diminutus and 
pronus from Libertad and Loreto. The latter is flatter above, with 









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78 



FIELDIANA: ZOOLOGY, VOLUME 50 



larger palatal teeth and a more open umbilicus, but otherwise is quite 
similar. 

The locality "Sagarmo" could not be found on any map available 
to me, but is presumed to be near Perene\ Dept. Junin. Preston's 
species is poorly figured, but the types show no characters separating 
them from the types of diminutus. The slightly larger basal tooth and 
bigger shell are not significant differences. Size variation in the Boca 
Inambari set is summarized in Table VII. 

Several sets in older collections labeled as yatesii (= ellipsostomus) 
were transferred to diminutus. The differences are primarily in the 
thicker, less sharply carinated shell, generally larger size and heavier 
teeth of diminutus. The differences are of degree rather than kind 
and the relationship of ellipsostomus and diminutus needs consider- 
able study. 

The single Brazilian shell (USNM 171453) was collected by Garbe 
in 1902 from an unknown locality on the Jurua River. Shape, tooth 
size and degree of carination are as in diminutus rather than ellip- 
sostomus. 

Labyrinthus pronus Pilsbry, 1932. Figure 20a-b. 

Labyrinthus pronus Pilsbry, 1932, Proc. Acad. Nat. Sci., Philadelphia, 84, 

pp. 389-390, pi. 28, figs. l,a,b— Uctubamba (sic), Dept. Libertad (error?), 

Peru at 7,000 feet elevation (M. A. Carriker!). 
Pleurodonte {Labyrinthus) baeri diminuta Haas, 1947 (not Gude, 1903), Fieldi- 

ana: Zool., 31 (22), pp. 172-173 — Yarinacocha, near Pucalpa, Loreto, 

Peru at 160 meters elevation (Schunke!). 

Range. — Peru, Libertad and Loreto. 

Material. — Peru: LORETO — Lago Yarina— Cocha, near Pucalpa 
at 160 meters elevation (CNHM 25867) ; Doma Santa Clara, 6° 55' S, 
Ucayali River Valley (USNM 601377). SAN MARTIN— Utcu- 
bamba (ANSP 159896 type). 




Fig. 20. Labyrinthus pronus, Utcubamba, 7,000 feet, Peru, ANSP 159896. 
Holotype. a, base; b, side. 



SOLEM: NEOTROPICAL LAND SNAILS 79 

Remarks. — Despite the difference in elevations and Utcubamba 
being located high above the Rio Huallaga while Pucalpa is on the 
Rio Ucayali, these appear to be the same species. The very flat spire, 
sharp angulation to the periphery, white lip and more strongly de- 
veloped teeth separate the shells from L. raimondii and L. diminutus. 
The Yarinococha shells are more elevated than the type, but other- 
wise are quite similar. Possibly L. diminutus is only subspecifically 
separable. 

Labyrinthus leprieurii (Petit, 1840). Figures 16b-d, 17a-d. 

Helix Le Prieurii Petit, 1840, Revue Zool., 1840, p. 74 — French Guiana. 
Helix leprieurii Petit, 1841, Guerin's Magazin de Zool., 1841, pi. 32; Pfeiffer, 

1848, Monog. helic. viv., 1, p. 400; Reeve, 1852, Conch. Icon., Helix, pi. 10, 

fig. 560; Pfeiffer, 1876, Monog. helic. viv., 7, p. 462. 
Helix auriculina Petit, 1840, Revue Zool., 1840, p. 74 — French Guiana; Petit, 

1841, Guerin's Magazin de Zool., 1841, pi. 33; Pfeiffer, 1848, Monog. helic. 

viv., 1, p. 400; Pfeiffer, 1852, Syst. Conch. Cab., I (12), 2, pp. 207-208, 

pi. 105, figs. 5-7; Pfeiffer, 1876, Monog. helic. viv., 7, p. 462. 
Helix bifurcata Reeve, 1852 (not Deshayes, 1838), Conch. Icon., Helix, pi. 100, 

fig. 554 — (French) Guiana. 
Helix (Labyrinthus) leprieurii Petit, Pilsbry, 1895, Man. Conch. (2), 5, pi. 174, 

pi. 40, figs. 96-99. 
Pleurodonte {Labyrinthus) leprieurii (Petit), Pilsbry, 1894, Man. Conch. (2), 

9, p. 95. 

Range. — "French Guiana" and two localities in Peru. 

Material. — French Guiana: No exact locality (CNHM 40763, 
CNHM 40766, Zurich, Edinburgh, ANSP 33174, ANSP 33175, 
ANSP 63581) . Peru: LORETO— Doma Santa Clara, Ucayali River, 
6°55'S (USNM 601357); SAN MARTIN— Moyobamba (CNHM 
40775, SMF 26379); Rio Huallaga (ZMA, Bartlett! 1867). 

Diagnosis. —The very sinuately twisted parietal lamella comes 
directly off the parietal lip; basal lip strongly sinuated with one large, 
broad knob; lower palatal wall with a large, slightly subequally bifid 
tooth, narrower upper portion slanted upward; aperture very strongly 
deflected; parietal and basal lips slightly to strongly deflected into 
umbilicus; periphery right angled or acutely angulated; spire moder- 
ately to strongly elevated; color brownish, usually with a yellowish- 
white peripheral band. Diameter 18.9-26.2 mm., H/D ratio 0.445- 
0.558. 

Remarks. — The nominate form has the lower palatal lip strongly 
indented at the bifid tooth, the basal and parietal lips deflected into 
the umbilicus, and is slightly larger (diameter 20.4-26.2 mm.) ; form 



80 FIELDIANA: ZOOLOGY, VOLUME 50 

auriculina has the outer palatal margin rounded, the basal and pari- 
etal lips only slightly deflected into the umbilicus, and is smaller 
(diameter 18.9-21.8 mm.). Except for the new Peruvian records, 
only specimens from old collections could be located. Considerable 
variation in apertural outline exists, but in the total absence of dis- 
tributional information its meaning cannot be assessed. The names 
auriculina and leprieurii recognized, respectively, the absence (fig. 
16d) or the presence (fig. 16c) of a marked flattening or indentation 
of the lower palatal lip. More striking is the degree to which the 
parietal and basal lips converge to become parallel and dip into the 
umbilicus (fig. 16b-d). The degree of change is very large, but inter- 
mediate conditions are present. The Loreto shells have the indented 
lower palatal lip of leprieurii, but the basal and parietal lips of auricu- 
lina, while the Moyobamba shell is typical auriculina. 

The original locality ("French Guiana") is probably erroneous. 

Labyrinthus tarapotoensis tarapotoensis (Moricand, 1858). 
Figures 21b, 22a. 

Helix tarapotoensis Moricand, 1858, Rev. et Mag. de Zool., 1858, p. 450, pi. 13, 

fig. 2— Tarapoto, Peru; Pfeiffer, 1868, Monog. helic. viv., 5, pp. 411-412; 

Pfeiffer, 1876, Ibid., 7, p. 462. 
Helix (Labyrinthus) tarapotoensis Moricand, Pilsbry, 1889, Man. Conch. (2), 

5, p. 170, pi. 64, figs. 17-18. 
Pleurodonte (Labyrinthus) dacostiana Haas, 1949 (not Preston, 1907), Fieldi- 

ana: Zoology, 31 (28), p. 236 — Divisoria, Cerro Azul, Huanaco, Peru at 

5,000 feet elevation (Schunke!). 

Range. — Known from scattered localities in the Rio Maranon, 
Putumayo, Rio Mayo and Rio Ucayali basins in Amazonian Peru. 

Material.— Peru: SAN MARTIN— Moyobamba (MCZ 87651). 
LORETO— Aguaitia River (=Aguanaitia?), Ucayali at 300 meters 
elevation (MCZ 159187). HUANACO— Divisoria, Cerro Azul, near 
Loreto border at 5,000 feet elevation (CNHM 30047, CNHM 30048). 
AM AZONAS— Balsas, Rio Maranon (USNM 116888). 

Remarks. — The white lip, obtusely angulated periphery, open um- 
bilicus and prominent teeth are the main characters separating this 
from the other species. The seven specimens show comparatively 
little variation in size, shape or apertural armature. Compared with 
L. t. baeri, the teeth are smaller and more sharply outlined, the um- 
bilicus slightly more widely open, and the shell smaller and more 
elevated. 



SOLEM: NEOTROPICAL LAND SNAILS 81 

Labyrinthus tarapotoensis baeri Dautzenberg, 1902. Figures 

21c, 22b. 
Helix (Labyrinthus) baeri Dautzenberg, 1902, Jour, de Conchy., 49 (4), pp. 306- 

307, pi. 9, figs. 1-3— Rfo Mixiollo, Huallaga, Peru (Baer!). 
Pleurodonte (Labyrinthus) baeri Dautzenberg, Haas, 1949, Fieldiana: Zool., 

31 (28), p. 235 — Cerro Azul, Rfo Ucayali, near Contamana, Loreto, Peru. 

Range.— Huallaga and Ucayali River basins in San Martin and 
Loreto, Peru. 

Material.— Peru: SAN MARTIN— Huallaga District (ANSP 
131428). LORETO— Cerro Azul, near Contamana (CNHM 30049, 
MCZ 159188, ANSP), Doma Santa Clara, 6° 55' S, Ucayali Valley 
(USNM 601370). 

Remarks. — The enlarged parietal tooth running into or near to the 
lip, obtusely angulated periphery, somewhat smaller umbilicus and 
white lip are the characters separating L. t. baeri and L. raimondii. 
Differences from L. t. tarapotoensis are given in the discussion of that 
form. The three known localities are far apart, the Rio Mixiollo be- 
ing a western tributary of the Rio Huallaga; the Cerro Azul lying on 
the east bank of the Rio Ucayali above Contamana, and Santa Clara 
lying downstream from Contamana. The specimens from Cerro Azul 
have the parietal lamella a little shorter and the periphery slightly 
more sharply angulated than in the figures of the type. They are also 
slightly smaller. Size variation is summarized in Table VII. The 
two examples from Doma Santa Clara were dead when collected. 
They are quite distinctive in having a very sinuated basal lip and 
deeply indented lower palatal lip. The lip form is very close to that 
seen in L. leprieurii (see fig. 16), although the parietal lamellae and 
lips are totally different. The effect of the lip sinuosity is to decrease 
the apertural opening, thus presumably lessening the chance of pre- 
dation. It is impossible to be certain that the Doma Santa Clara 
shells actually are baeri, but they are nearest to this morph. 

Labyrinthus raimondii (Philippi, 1867). Figures 21d, 22c. 

Helix raimondii Philippi, 1867, Malak. Blatt., 14, p. 65 — between Santa Cata- 
lina and Yanayaco, Dept. Loreto, Peru; Pfeiffer, 1867, Novit. Conch., 3, 
pp. 329-330, pi. 79, figs. 7-9; Hidalgo, 1869, Viage al Pacifico, Moll., p. 17, 
pi. 2, figs. 4-5— Napo, Ecuador; Pfeiffer, 1876, Monog. helic. viv., 7, 
pp. 461-462. 

Labyrinthus raimondii (Philippi), Miller, 1878, Malak. Blatt., 25, p. 167; 
Cousin, 1887, Bull. Soc. Zool. France, 12, p. 64— Napo. 

Helix (Labyrinthus) raimondii Philippi, Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 172-173, pi. 40, figs. 91-95. 



82 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 21. Apertures of: a, Labyrinthus diminutus, Perene, Junin, Peru. Edin- 
burgh. Lectotype; b, Labyrinthus tarapotoensis, Divisoria, Cordillera Azul, Peru, 
CNHM 30047; c, Labyrinthus t. baeri, Cerro Azul, Rio Ucayali, Peru, CNHM 
30049; d, Labyrinthus raimondii, Napo River Valley, Ecuador, CNHM 117841; 
e, Labyrinthus furcillatus, "Ecuador," CNHM 132549;/, Labyrinthus bifurcatus, 
"Quito, Ecuador," CNHM 40765. Scale line equals 10 mm. 



Pleurodonte (Labyrinthus) fragilis Haas, 1949, Arch. f. Mollusk., 78 (4-6), 
p. 155, pi. 7, fig. 3 — forest near Belterra, Lower Rio Tapajoz, Brazil (Sioli!). 

Pleurodonte (Labyrinthus) manuelis (sic) Haas, 1955 (not Higgins, 1872), Fieldi- 
ana: Zool., 34 (35), p. 368 — Rio Ucayali, near Pucalpa, Dept. Loreto, 
Peru at 200 meters elevation (Schunke!). 

Range. — Amazonian basin from Amazonas and Caqueta in Co- 
lombia to southern Loreto in Peru and the Rio Tapajoz in Para, 
Brazil. There are two records from the Rio Esmereldas drainage on 
the Pacific slopes of the Ecuadorean Andes (Mindo and Santo Do- 
mingo de los Colorados). 



SOLEM: NEOTROPICAL LAND SNAILS 



83 






Fig. 22. Shells of: a, Labyrinthus tarapotoensis, Divisoria, Cordillera Azul, 
Peru, CNHM 30048; b, Labyrinthus t. baeri, Cerro Azul, Rio Ucayali, Peru, 
CNHM 30049; c, Labyrinthus raimondii, Napo River Valley, Ecuador, CNHM 
117841; d, Labyrinthus furcillatus, "Ecuador," CNHM 132549; e, Labyrinthus 
bifurcatus, "Quito, Ecuador," CNHM 40765. Scale line equals 10 mm. 



Material. — Normal form. Peru: LORETO — Yurimaguas, Rio 
Mayo (CNHM 40759) ; Alto Yavari, zone of mouth of Rio Yaquerana 
(CNHM 67593); Contamana at 160 meters (SMF 141097); near 
Pucalpa, Rio Ucayali at 200 meters elevation (CNHM 30703) ; Borja, 
Rio Maran6n (CNHM 95655); Alto Amazonas, Rio Morona, mouth 
of Rio Amayo (CNHM 67892). Ecuador: No exact locality (Zurich, 
Edinburgh, CNHM 251, CNHM 100133); Nachiyacu (ANSP 170705, 
Jackson 4715); Napo (Jackson 5296, MCZ 92315, CNHM 86696, 
CNHM 117839); Napo River Valley (CNHM 117841); Sarayaco, 
Rio Bobonaza at 400 meters (SMF 156309) ; Chicherota, Bobonaza 
River, Pastaza River (ANSP); Puyo at 1,000 meters elevation 
(CNHM 117838); Mindo (Jackson 4814); Jatamyacu at 700 me- 



84 FIELDIANA: ZOOLOGY, VOLUME 50 

ters (CNHM 117840, MCZ 64956); Mera (Jackson 5518); Milpe 
(Jackson 4819); Santo Domingo de los Colorados (Jackson 9745). 
Colombia: PUTUMAYO— La Tagua (SMF 162666) ; Puerto Legui- 
zamo (CNHM 114002); Rio Mecaya, tributary of Upper Caqueta 
River (CNHM 114000); Las Lomitas, Rio Sencella, Upper Ca- 
queta River (CNHM 114001); CAQUETA— Cano La Duche, abajo 
de la Colonia de Araracuara (CNHM 114107) ; El Salado, below Curi- 
playa, Upper Caqueta River (CNHM 114143). Brazil: PARA— 
Belterra, Rio Tapajoz (CNHM 30399, holotype of fragilis Haas). 

Dwarf form. Peru: LORETO — Rio Samaria, Santa Elena, Iqui- 
tos at 130 meters elevation (CNHM 64407) ; Rio Nanay, Santa Luisa, 
Iquitos at 160 meters elevation (CNHM 64406) ; Pucalpa, Rio Ucay- 
ali at 200 meters elevation (CNHM 47099) ; Colonia Calleria, Rio 
Calleria, 15 km. from Ucayali (CNHM 114186). Brazil: PARA— 
Ford's Rubber Plantation, Rio Tapajoz, Bon Vista (ANSP 166721). 

Remarks. — The acutely angulated to carinated periphery and 
brownish tone of the lip and teeth are the main identifying char- 
acters. In pronus the spire is flatter, the lip white, and the basal lip 
seemingly more sinuated, while in diminutus the shell is small, less 
carinated and the lip is white. L. furcillatus differs only in having 
the two arms of the lower palatal lamella farther apart. It probably 
is not specifically distinct, but in the absence of localized material is 
separated. 

The original specimens of raimondii from near Yanayacu on the 
Bajo Ucayali and those reported by Hidalgo (1869) from "Napo," 
Ecuador were quite large, diameter 45 and 51 mm., respectively. Of 
the modern specimens, only a few shells reach this size. Most are 
between 35.5-43.4 mm. in diameter. However, five "dwarf" speci- 
mens are 22.4-28.2 mm. in diameter. An interesting set of four 
specimens (CNHM 67892 from Alto Amazonas, Rio Morona, mouth 
of Rio Amayo, Dept. Loreto) has diameters of 31.8, 35.8, 41.8 and 
41.9 mm., indicating the extent of size variation. The two larger 
shells have the parietal lip only slightly free of the wall and the outer 
palatal lip slightly sinuated, while in the two smaller the parietal lip 
is further removed from the wall and the lower palatal lip becomes 
progressively more sinuated. The largest shell has the spire evenly 
elevated with flatter sides, while the three smaller have less elevated 
spires with rounded sides. No separation into two forms is possible, 
since intermediate conditions can be found among most of the other 
available specimens. Another slight variation is seen in a small set 



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86 FIELDIANA: ZOOLOGY, VOLUME 50 

(3 examples) from the Rio Yaquerana on the Peruvian-Brasilian 
border (CNHM 67593). Here the parietal lip is much more accentu- 
ated and free of the penultimate whorl, the parietal lamella is longer 
and slightly sinuated, and only one of the three specimens shows a 
trace of brownish cast to the lip. The diameters are 34.6, 36.8, and 
43.3 mm. This is the only set tending toward the baeri type. In 
some of the smaller specimens the aperture is rather constricted by 
the presence of an inward sinuation of the lower palatal lip, much as 
in the typical form of L. leprieurii. 

The five specimens from Loreto and Para referred to as a "dwarf 
form" are quite interesting. Not only are they much smaller (see 
Table VII), but their D/U ratio is larger than in the normal forms. 
In the latter the distribution of the D/U ratio is: 



Ratio 


6.2 


6.7 


7.2 


7.7 


8.2 


8.7 


Number of 














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2 


5 


9 


22 


24 


21 


Ratio 


9.2 


9.7 


10.2 


10.7 


11.2 


11.7 


Number of 














examples 


14 


8 


4 


2 


1 


1 



In tooth structure, color, shape and spire, the smaller shells do not 
differ significantly from the larger. Possibly they represent a dwarf 
ecological form. 

The holotype of L. fragilis Haas is a very thin, probably subadult 
shell. Its moderately open umbilicus (D/U ratio 10.2) probably is 
caused by the subadult lip condition. It is, however, within the range 
of variation of normal raimondii. Similarly, the diameter (37.3 mm.) 
is not unusual. The H/D ratio (0.502) is large, but not beyond the 
known range of variation. In view of the fact that the other shell 
from Para (ANSP 166721) is the dwarf form of raimondii, synonymi- 
zation of fragilis and raimondii seems probable. 

Labyrinthus furcillatus (Hupe\ 1853). Figures 21e, 22d. 

Helix furcillata Hupe, 1853, Rev. et Mag. de Zool., 1853, pp. 302-303, pi. 11, 
fig. 2 — Huancavelica, Peru; Pfeiffer, 1855, Novit. Conch., 1, pp. 58-59, 
pi. 17, figs. 3-4 ("H. erecta" on plate caption) — Meobamba, Peru (Yates!); 
Hupe, 1857, in Castelnau's Exped. Amer. Sud., Moll., pp. 18-19, pi. 3, 
fig. 1; Pfeiffer, 1859, Monog. helic. viv., 4, pp. 304-305; Pfeiffer, 1876, 
Ibid., 7, p. 462. 

Helix (Labyrinthus) furcillata Hupe, Pilsbry, 1889, Man. Conch. (2), 5, pp. 
171-172, pi. 39, figs. 91-92. 

Labyrinthus furcillatus (Hupe), Miller, 1878, Malak. Blatt., 25, p. 167; Cousin, 
1887, Bull. Soc. Zool. France, 12, p. 63. 



SOLEM: NEOTROPICAL LAND SNAILS 87 

Range. — Peru, San Martin and Huancavelica. 

Material— "Amazone" (USNM 515467) ; "Peru" (ANSP 113573, 
Edinburgh); "Ecuador" (Zurich, CNHM 132549); "Parana-Pura" 
(MCZ 146119); "Tarapoto, Peru" (SMF 172170); "New Granada" 
(SMF 172172); "Pebas, LORETO" (SMF 172161). 

Remarks. — The white to brownish lip, rounded or obtusely angu- 
lated periphery and open umbilicus are as in L. tarapotoensis. The 
main difference lies in furcillatus having the two arms of the bifurcated 
lower palatal tooth widely separated, while in tarapotoensis and rai- 
mondii they are much closer together. The constancy and importance 
of this character are unknown. The only known records of this spe- 
cies date from the 1850's, and no reliable locality records exist. 

Labyrinthus bifurcatus (Deshayes, 1838). Figures 21f, 22e. 

Helix bifurcata Deshayes, 1838, Guerin's Magasin de Zool., 1838, class 5, 
pi. Ill, fig. 2; Pfeiffer, 1848, Monog. helic. viv., 1, p. 379; Pfeiffer, 1852, 
Syst. Conch. Cab., I (12), 2, p. 207, pi. 105, fig. 1; Pfeiffer, 1859, Monog. 
helic. viv., 4, p. 305 — Meobamba, Peru; Pfeiffer, 1876, Monog. helic. viv., 
7, p. 462. 

Helix (Labyrinthus) bifurcata Deshayes, Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 170-171, pi. 64, figs. 22-23. 

Range. — Unknown. 

Material.— Ecuador: "Quito" (CNHM 40765). "New Granada" 
(Edinburgh, Zurich). 

Remarks. — The original specimen was probably subadult and is 
from an unknown locality. The white lip, obtusely rounded periph- 
ery and partially obscured umbilicus are the main characters of this 
form. The size of the type is diameter 37 mm., height 15 mm. 

No accurately localized examples were seen. It may be that this 
species is based on extreme variants of furcillatus or tarapotoensis. 
The few examples located were all small, diameter 29.4-34.5 mm. 
(mean 31.4 mm.), with rather markedly elevated spire, H/D ratio 
0.432-0.545 (mean 0.508). 

Group of Labyrinthus aenigmus 

The species grouped here show more geographical unity than 
morphologic identity. Except for L. clappi Pilsbry from the Sierra 
Nevada de Santa Marta, they are known only from the Cauca, Atrato 
and Magdalena River basins north of 5° N. latitude. L. o. assimilans 
and L. o. otostomus have not been reported from an exact locality, and 
the others are known from only a single locality or from plantations 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 23. Apertures of: a, Labyrinthus aenigmus, no locality, USNM 354647; 
b, Labyrinthus clappi Los Nubes Estate, 5,000 feet elevation, Sierra Nevada de 
Santa Marta, Colombia, CNHM 132086; c, Labyrinthus o. otostomus, Colombia. 
Edinburgh; d, Labyrinthus o. bogotensis, "New Granada," CNHM 40758. Scale 
line equals 10 mm. 



within a limited geographic area. The imperforate L. clappi does not 
have the lower parietal lip fused with the parietal lamella, while the 
other species have the type of fusion found in L. manueli, L. vexans 
and L. magdalenensis. L. aenigmus has a nearly closed umbilicus, 
very sinuated twisted basal lip and strong palatal teeth, but no basal 
tooth. The very closely related L. o. bogotensis, L. o. otostomus and 
L. o. assimilans have a double lower palatal tooth that is unique in 
having the two arms parallel rather than diverging as in the rai- 
mondii series. 

Gude (1912) proposed a new genus, Ambages (type species: Helix 
vexans Dohrn, 1875 by original designation) , for L. vexans, L. aenig- 
mus, L. assimilans and L. sharmani. Ambages was characterized by 
the teeth being more developed than in Isomeria and the shell more 
sub-globose than in Labyrinthus. The shell shape is not importantly 
different and L. vexans, the type species of Ambages, is separable only 
with great difficulty from several species of Labyrinthus. A better 



SOLEM: NEOTROPICAL LAND SNAILS 



89 




Fig. 24. Shells of: a, Labyrinthus aenigmus, no locality, USNM 354647; 
6, Labyrinthus clappi, Los Nubes Estate, 5,000 feet elevation, Sierra Nevada de 
Santa Marta, Colombia, CNHM 132086; c, Labyrinthus o. otostomus, Colombia. 
Edinburgh; d, Labyrinthus o. bogotensis, "New Granada," CNHM 40758. Scale 
line equals 10 mm. 

case could have been made for separation of L. aenigmus and L. 
clappi, but L. vexans is nearly typical Labyrinthus. 

KEY TO THE LABYRINTHUS AENIGMUS GROUP 

1. Umbilicus at least partly open 2 

Umbilicus completely closed Labyrinthus clappi Pilsbry, 1901 

2. Lower palatal lip with 2 parallel lamellae or one lamella with a strong upper 

buttress 3 

Lower palatal lip with one lamellar tooth. 

Labyrinthus aenigmus (Dohrn, 1875) 

3. Basal lip with two teeth 4 

Basal lip with one tooth Labyrinthus o. otostomus (Pfeiffer, 1852) 

4. Periphery acutely carinated; diameter 37 mm. 

Labyrinthus o. bogotensis (Pfeiffer, 1854) 
Periphery nearly a right angle; diameter 26 mm. 

Labyrinthus o. assimilans Smith, 1897 

Labyrinthus aenigmus (Dohrn, 1875). Figures 23a, 24a. 

Helix (Isomeria) aenigma Dohrn, 1875, Jahrb. deutsch. Malak. Gesell., 2, 
pp. 292-294, pi. 10, figs. 1-2— Frontino, Antioquia, Colombia at 6,000 feet 



90 FIELDIANA: ZOOLOGY, VOLUME 50 

elevation; Pfeiffer, 1876, Monog. helic. viv., 7, p. 591; Dohrn, 1886, Syst. 
Conch. Cab., I (12), 4, pp. 625-626, pi. 180, figs. 1-2; Pilsbry, 1889, Man. 
Conch. (2), 5, p. 158, pi. 39, figs. 93-94, pi. 44, figs. 1-2. 
Pleurodonle (Isomeria) aenigma (Dohrn), Pilsbry, 1894, Man. Conch. (2), 9, 
p. 94. 

Range. — Known only from the type collection. 

Material— "New Granada" (ANSP 30647, MCZ 74568, USNM 
354647, Zurich). Colombia: ANTIOQUIA— Frontino (Zurich, para- 
types). 

Diagnosis. — The parietal lamella is high and continuous with the 
moderately elevated lower parietal lip (which is much lower than the 
lamella), while the upper parietal lip is greatly reduced in prominence 
and inserts perpendicularly into the lamella; the basal lip is very sin- 
uated and has a strong terminal swelling, but is not toothed; the 
lower palatal lip has a prominent crescentic lamella twisted inward 
posteriorly; upper palatal lip with a lower, broadly rounded lamella; 
umbilicus nearly closed by basal and parietal lips; periphery angu- 
lated at nearly 90°. Diameter 46-49 mm. (mean 46.9 mm.), H/D 
ratio 0.497-0.550 (mean 0.522). 

Remarks. — The absence of the basal tooth, very sinuated basal lip, 
much larger size and strongly angulated periphery easily separate 
aenigmus from vexans, which has a nearly straight basal lip with two 
teeth, a much more open umbilicus and the lower parietal lip is not 
reduced in height. 

The only known locality is Frontino, all museum material being 
either paratypic or from "New Granada." 

Labyrinthus clappi Pilsbry, 1901. Figures 23b, 24b. 

Pleurodonte (Labyrinthus) clappi Pilsbry, 1901 (July), Nautilus, 15 (3), pp. 34- 
35, pi. 2, figs. 3-4 — Alto de Cielo, 5,000 feet elevation, Sierra de Santa 
Marta, Magdalena, Colombia in forest among rotting leaves on ground. 

Labyrinthus colombiensis Da Costa, 1901 (December), Ann. Mag. Nat. Hist. 
(7), 8, pp. 557-558, 2 figs.— Santa Marta, Colombia. 

Range. — Colombia, Sierra Nevada de Santa Marta, probably at 
higher elevations only. 

Material— Colombia (Edinburgh): MAGDALENA— Sierra Ne- 
vada de Santa Marta (CNHM 40771, USNM 307449); Los Nubes 
Estate, Sierra Nevada de Santa Marta at 4,000 feet (CM 62.16585, 
USNM 171917, CNHM 132086) ; Don Amo Estate, 4,000 feet ele- 
vation, Sierra Nevada de Santa Marta (ANSP 83168, CM 4530); 
Alto de Cielo, Sierra Nevada de Santa Marta, 5,000 feet elevation 
(CM 4091). 



SOLEM: NEOTROPICAL LAND SNAILS 91 

Diagnosis. — The sinuated parietal lip is appressed to the wall with 
a thick raised edge; high curved parietal lamella descending to join 
edge of lower portion of the parietal callus; basal lip nearly straight 
with two very prominent thick lamellae; lower palatal wall with sin- 
gle high, crescentic lamella twisted slightly downward; upper palatal 
wall with a smaller conical lamella twisted slightly upward, laterally 
buttressed; umbilicus completely closed; periphery obtusely angu- 
lated, with slight keel. Diameter 30.6-34.5 mm. (mean 32.9 mm.), 
H/D ratio 0.554-0.648 (mean 0.595). 

Remarks. — The completely closed umbilicus, very prominent teeth 
and appression of the parietal lip to the wall easily separate L. clappi 
from other Labyrinthus. The only other species with closed umbili- 
cus, L. sieversi (Martens) also from the Sierra Nevada de Santa Marta, 
has a less sinuated parietal lip that the parietal lamella fails to reach, 
quite differently constructed palatal teeth, and is much, much smaller 
(diameter 17.4-19.0 mm.). I doubt that clappi and sieversi will be 
found to be very closely related. Probably they were separately de- 
rived from the isodon complex. 

All known localities for L. clappi are from the rather isolated 
northwest spur of the Sierra Nevada. Both Don Amo Estate and 
Los Nuves (=Los Nubes) are on the north face of the spur below the 
peak named La Horqueta. The known altitudes of 4,000-5,000 feet 
are well below the apparent habitat of the new species Isomeria me- 
demi (see p. 00) that has recently been collected at 8,200 to 8,850 feet 
on the San Lorenzo ridge in the same mountain mass. L. sieversi has 
been collected only on the north face and the northeast spur of the 
main mass of the Sierra Nevada de Santa Marta. 

Labyrinthus otostomus otostomus (Pfeiffer, 1852). Figures 23c, 
24c, 25a. 

Helix siostoma (sic) Pfeiffer, 1852, in Reeve's Conch. Icon., Helix, pi. 100, 

fig. 551 — Andes of Colombia. 
Helix otostomus Pfeiffer, 1853, Proc. Zool. Soc. London, 1851, p. 260; Pfeiffer, 

1853, Monog. helic. viv., 3. pp. 255-256. 
Helix (Labyrinthus) otostoma Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, p. 176, 

pi. 64, fig. 29. 
Pleurodonte (Labyrinthus) otostoma (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 

9, p. 96. 

Range. — Unknown . 
Material. — Colombia (Edinburgh). 

Diagnosis. — The high parietal lamella is continuous with the ele- 
vated lower lip, while the upper parietal lip is greatly reduced in size 



92 



FIELDIANA: ZOOLOGY, VOLUME 50 







Fig. 25. Parietal lips in Labyrinthus o. otostomus and Labyrinihus o. bogotensis: 
a, Labyrinthus o. otostomus; b, Labyrinthus o. bogotensis. 

and inserts onto the lamella at a nearly perpendicular angle; basal lip 
moderately sinuated with one prominent crescentic lamellar tooth 
and a trace of an inner tooth; lower palatal lip with two closely set 
teeth as in bogotensis, upper reduced to forming edge to callus; upper 
palatal wall with a single triangular supraperipheral tooth; umbilicus 
moderately open; periphery acutely carinated. Diameter 32 mm., 
H/D ratio 0.477. 

Remarks. — L. o. otostomus is obviously very closely related to L.o. 
bogotensis. The comparatively minor differences are in the much 
greater reduction of the upper parietal lip and loss or very great re- 
duction of the inner basal tooth in L. o. otostomus. This subspecies 
has never been reported from an exact locality. L. o. bogotensis may 
be only an extreme variant. 



Labyrinthus otostomus bogotensis (Pfeiffer, 1854). Figures 23d, 
24d, 25b. 

Helix bogotensis Pfeiffer, 1854, in Reeve's Conch. Icon., Helix, pi. 196, fig. 1381 
— Santa Fe de Bogota, Colombia; Pfeiffer, 1855, Proc. Zool. Soc. London, 
1854, p. 288; Pfeiffer, 1859, Monog. helic. viv., 4, pp. 305-306. 



SOLEM: NEOTROPICAL LAND SNAILS 93 

Helix (Labyrinthus) bogotensis Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, 

p. 176, pi. 42, fig. 40. 
Plenrodonte (Labyrinthus) bogotensis (Pfeiffer), Pilsbry, 1894, Man. Conch. 

(2), 9, p. 96. 

Range.— Known only from the type locality. 

Material.— Colombia: "New Granada" (CNHM 40758); Santa Fe 
de Bogota (ANSP 33168, SMF, SMF 82536, ZMA, Edinburgh, para- 
types); BOYACA— Muzo (ANSP 174437, MCZ 64931). 

Diagnosis.— The parietal lamella is very high and continuous with 
the strongly elevated lower parietal lip, while the upper parietal lip 
is distinctly lower and slants into the lamella; basal lip slightly sinu- 
ated with two prominent teeth, inner smaller; lower palatal lip with 
two nearly parallel teeth set closely together and joined by a callus, 
upper tooth distinctly lower or reduced to forming edge of callus; 
periphery slightly reflected to form a weak spout with upper palatal 
margin extended inward to form a blunt triangular tooth; umbilicus 
slightly less than half closed by basal and parietal lips; periphery 
acutely carinated, spire somewhat flattened. Diameter 29.1-40.4 
mm. (mean 35.1 mm.), H/D ratio 0.393-0.478 (mean 0.430). 

Remarks. — The higher upper parietal lip and prominent inner 
basal tooth separate bogotensis from otostomus. The conical upper 
palatal tooth and two lower palatal teeth are the characters immedi- 
ately separating it from vexans and aenigmus. 

Labyrinthus otostomus assimilans E. A. Smith, 1897. Figure 
26a-b. 

Labyrinthus assimilans E. A. Smith, 1897, Jour, of Malac, 6 (2), p. 27, pi. 4, 
figs. 6-8 — Cauca River, Colombia. 

Range.— Known only from the type collections. 

Diagnosis. — The parietal lamella is very high and continuous with 
the lower parietal lip, the upper lip being reduced in size; basal lip 
very slightly sinuated with two prominent teeth; lower palatal lip 
with two prominent, close-set teeth, upper distinctly smaller; periph- 
ery slightly reflected forming a spout with a small conical pointed 
tooth on the lower margin of upper palatal lip; umbilicus but slightly 
covered by basal and parietal lips; periphery nearly right angled. 
Diameter 26 mm. 

Remarks. — According to Smith, this species is very near to bogo- 
tensis, but is ". . . much smaller (in) size and (with) much more obtuse 
periphery. The peristome also is not so produced or pointed in front, 



94 



FIELDIANA: ZOOLOGY, VOLUME 50 



the sinus between the tubercle within the upper margin and the large 
double tooth within the front margin being shallower and of a differ- 
ent form." 








Fig. 26. Types from the British Museum: a-b, Labyrinthus o. assimilans, 
Cauca River, Colombia, BM(NH) 97.7.26.7-8 (a, side; b, aperture); c-d, Labyrin- 
thus sharmani, Alejandria, Antioquia, Colombia, BM(NH) 1912.1.27.1 (c, side; 
d, aperture). Reproduced by permission of the British Museum (Natural History). 



The two types in the British Museum (Natural History) (97.7.26. 
7-8) are the only known examples. 

Group of Labyrinthus unciger 

The two species have one basal and one sinuated parietal lamella, 
a lower palatal lamella surmounted by a deeply recessed, hooked 
(usually) or "T"-shaped tooth, lenticular form and a protruded knife- 
edge peripheral keel. Form of the aperture and of the basal and pari- 
etal lamellae are readily derivable from members of the isodon complex. 
The unique structure of the palatal lamella with its entering ridge or 
callus and the posterior hooked tooth or "T"-shaped lamella seems to 
present no similarity with the structures found in other Labyrinthus, 
but could be derived from the palatal tooth type of L. triplicatus. 

The smaller, spirally-color-banded L. unciger probably ranges 
from Lim6n, Costa Rica to somewhere in Choc6, Colombia at low 
to moderate elevations. The larger, unicolored L. creveauxianus is 



SOLEM: NEOTROPICAL LAND SNAILS 95 

known only from Frontino, Antioquia, Colombia. Possibly it may 
be found at higher elevations in Dari£n, Panama. 

Species recognition is most easily accomplished by the presence 
of red spiral sub- and supra-sutural bands in L. unciger and the uni- 
color of L. creveauxianns. There are also structural differences, par- 
ticularly in the curvature of the parietal lip (lower and outer edge 
concave in unciger; higher and outer edge straight or convex in cre- 
veauxianus) , length of the parietal lamella (short of lip in unciger; 
running into lip in creveauxianus), and more rounded spire in unciger. 
In creveauxianus the tooth is a twisted, hooked structure usually 
without strong lateral supports, while in unciger it varies greatly (see 
fig- 29). 

Labyrinthus unciger (Petit, 1838). Figures 27a-b, 29. 

Carocolla uncigera Petit, 1838, Guerin's Mag. de Zool., 1838, pi. 113 — Panama 

(Pavageau!). 
Helix uncigera (Petit), Pfeiffer, 1848, Monog. helic. viv., 1, pp. 398-399; De- 

shayes, 1851, Hist. Nat. Moll., 1, pp. 385-386, pi. 45B, figs. 2-3; Pfeiffer, 

1852, Syst. Conch. Cab., I (12), 2, p. 206, pi. 104, figs. 8-10 (plate issued 

in 1850); Reeve, 1852, Conch. Icon., Helix, pi. 100, fig. 552. 
Helix (Labyrinthus) uncigera (Petit), Pilsbry, 1889, Man. Conch. (2), 5, pp. 

164-165, pi. 42, figs. 23-26 (form chiriquiensis Pilsbry, 1910); Kobelt, 

1893, Syst. Conch. Cab., I (12), 4, p. 632, pi. 181, figs. 13-14. 
Helix uncigera var. conoidea Ancey, 1890, Bull. Soc. Malac. France, 7, p. 152 — 

Colombia. 
Helix uncigera var. anopla Ancey, 1890, loc. cit., 7, p. 152 — Colombia. 
Caracolla uncigera (Petit), Pilsbry, 1893, Man. Conch. (2), 8, p. 264. 
Pleurodonte (Labyrinthus) tenaculum Dall, 1909, Smith. Misc. Coll., 52 (3), 

pp. 361-362, fig. 64, pi. 37, figs. 5, 6, 10, 11— mountains of Atrato River, 

"Sierra Darien," Panama (A. E. Heighway!). 
Pleurodonte (Labyrinthus) uncigera (Petit), Pilsbry, 1910, Proc. Acad. Nat. 

Sci., Philadelphia, 1910, p. 506, fig. 1; Pilsbry, 1926, op. cit., 78, pp. 75-76, 

fig. 6c, pi. 9, fig. 6 — Rio Puerco (=Pucro), Darien, Panama. 
Pleurodonte (Labyrinthus) uncigera chiriquiensis Pilsbry, 1910, Proc. Acad. 

Nat. Sci., Philadelphia, 1910, pp. 506-507, fig. 2— Chiriquf (Lagoon), 

Panama. 

Pleurodonte (Labyrinthus) chiriquiensis Pilsbry, 1926, op. cit., 78, p. 76, fig. 6b, 
pi. 9, fig. 5. 

Pleurodonte (Labyrinthus) chiriquiensis mutant tau Pilsbry, 1926, loc. cit., 78, 
p. 76, fig. 6a — Mono Creek, Almirante and Bocas del Toro Island (A. A. 
Olsson!). 

Range. — Atlantic drainage of Panama from Costa Rica border to 
the lower reaches of the Atrato River basin in Colombia. Probably 
will be found in Lim6n, Costa Rica. 



96 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 27. Shells of: a-b, Labyrinthus unciger form chiriquiensis, Club Cam- 
pestre, Panama, CNHM 73371 (a, base; b, side); c-d, Labyrinthus creveauxianus, 
Frontino, Colombia. Basel 432a. Lectotype (c, side; d, top). Scale line equals 
10 mm. 



Material— Form unciger — Colombia: CHOCO — Arquia, 1)4 hours' 
walk from Unguia (CNHM 113998, CNHM 114110); Acandi (ANSP 
164970) ; Golfo de Uraba (R. Wright Barker) ; mountains near mouth 
of Atrato River (USNM 111073 types of tenaculum Dall, 1909). Pan- 
ama: DARIEN— Rio Pucro (ANSP 140305). PANAMA— mountains 
around Gaspasalama, upper Mamoni River (USNM 228906); half 
way from Cerro Azul to Mandingo (ANSP 243693) ; Cerro Campana 
(MCZ, CNHM 132552). COM ARC A DE SAN BLAS— Puerto 
Obaldia (USNM 228666). CANAL ZONE— No exact locality 
(USNM 225984); Rio Pequeni (MCZ 133476); Salamanca Hydro- 
graphic Station, Rio Pequeni at 300 feet elevation (MCZ 111174). 

Form tau— Colombia: CHOCO— Acandi (USNM 341768). Pan- 
ama: COLON— Rio Salud (ANSP 155387, USNM 618724). COCLE 



SOLEM: NEOTROPICAL LAND SNAILS 



97 



—El Valle (MCZ 88933). BOCAS DEL TORO— Mono Creek, Almi- 
rante (ANSP 140304) ; Bocas del Toro Island (ANSP 140303 types 
of tau). 




Fig. 28. Aperture of: Labyrinthus creveauxianns, Frontino, Colombia. Basel 
432a. Lectotype. Scale line equals 10 mm. 



Form chiriquiensis — Panama: PANAMA — Cerro Campana 
(MCZ, CNHM 117647). CANAL ZONE— near Madden Lake 
(CNHM 56590). COCL&— El Valle (CNHM 63774, CNHM 63775, 
ANSP 226842) ; El Valle at 2,400 feet elevation (USNM 596736) ; trail 
to Las Minas (ANSP 163476) ; Club Campestre, El Valle (CNHM 
73371, CNHM 73377, CNHM 73410, CNHM 73584, CNHM 84492). 
BOCAS DEL TORO— Chiriqui Lagoon (ANSP 5612 types of chiri- 
quiensis) . 

Diagnosis. — The prominent, slightly sinuately twisted lamella does 
not reach the only slightly elevated parietal lip; parietal lip with outer 
edge slightly concave; basal lip with single knob-like tooth; lower 
palatal wall with or without an entering lamellar ridge, posteriorly 
with a hooked to "T"-shaped tooth (fig. 29a-f); periphery acutely 
carinated with protruding knife-edge keel; umbilicus only slightly 
obscured by extension of basal and parietal lips; spire normally ele- 
vated, rounded above; color yellow- white to light yellow-brown with 
spiral red sub- and supra-sutural color bands. Diameter 23.9-33.8 
mm., H/D ratio 0.322-0.454. 



98 



FIELDIANA: ZOOLOGY, VOLUME 50 









Fig. 29. Palatal tooth variation in Labyrinthus unciger; a, Form tau, Bocas 
del Toro Island, Panama, ANSP 140303. Lectotype of tau Pilsbry, 1926; b, Form 
chiriquiensis, on trail from El Valle to Rfo La Mina, Code Province, Panama, 
ANSP 162476; c, Form chiriquiensis, Chiriqui Lagoon, Panama, ANSP 5612. 
Lectotype of chiriquiensis Pilsbry, 1910; d, Form chiriquiensis, Club Campestre, 
El Valle, Code Province, Panama, CNHM 73371; e-f, Form unciger, Acandi, 
Choc6, Colombia, ANSP 164970, showing smooth (e) and fluted (/) ridge of lower 
palatal tooth. 



Remarks. — Pilsbry (1926, p. 76) considered unciger and chiriqui- 
ensis distinct species and that tau was a mutant form of chiriquiensis. 
The differences were based on the structure and position of the pal- 
atal tooth. In typical unciger there is a lower palatal ridge arising 
just below the periphery that becomes markedly elevated with grad- 
ual posterior descension and slants diagonally backward. A large, 
slightly twisted, hook-like tooth, usually with a faint trace of an 



SOLEM: NEOTROPICAL LAND SNAILS 99 

outer lateral support, arises from the posterior edge of the lamella. 
The anterior edge of the ridge may be smooth (fig. 29e) or fluted 
(fig. 29f ) . The tip of the hook points downward (see fig. 29e, f ) . At 
Cerro Campana and El Valle, the anterior ridge has been reduced to 
a low callus and the hook-like tooth has developed very prominent 
outer and inner lateral projections and an extensive supporting but- 
tress under the posterior two- thirds of the tooth (fig. 29d) . The tooth 
still occupies the same relative position in the aperture. In the types 
of chiriquiensis, the tooth is located much nearer to the apertural 
edge, the inner lateral projection is very large, and the free portion 
is much shorter (fig. 29c). A few shells have the tooth joined to the 
base of the shell with only a slight ovate opening separating the tooth 
edge and buttress (fig. 29b) . From this to form tau (fig. 29a) involves 
only closure of the opening separating the tooth edge and buttress. 
In the latter the tooth has turned into a "T"-shaped lamella with 
nearly vertical anterior descension. 

The gradual shift in the tooth structure suggests classic clinal 
variation, but is complicated by both tau and unciger having been 
recorded from Acandi and both unciger and chiriquiensis at Cerro 
Campana. The collections, in both cases, were made at different 
times and could easily have been samplings of different local popu- 
lations. Except for the Acandi, Colombia examples, all specimens 
from the Canal Zone south are unciger, which also reaches Cerro 
Campana, while those from the Canal Zone to Bocas del Toro are 
chiriquiensis and tau, except for the Cerro Campana unciger. The 
palatal tooth is located much farther back in the unciger form than 
in chiriquiensis and tau, and in every case tooth position follows tooth 
structure. Pending collections to determine the status of the Cerro 
Campana and Acandi mixture of forms, I prefer to treat these as 
nomenclaturally neutral "forms" rather than to recognize unciger and 
chiriquiensis as subspecies. 

The striking color pattern of spiral reddish-brown bands on a 
yellowish- white background is diagnostic among Panama species and 
is only matched in Labyrinthus by L. dunkeri (Pfeiffer) from San- 
tander, Magdalena and Goajira in Colombia. The latter is smaller 
with quite different dentition, the two basal and three palatal teeth 
at once separating them. 

Size variation is moderately large between localities, but shows no 
obvious geographical trend. The vast majority of the specimens were 
between 28 and 31 mm. in diameter, with very few appreciably larger 
or smaller. The largest specimens were those from Arquia (CNHM 



100 FIELDIANA: ZOOLOGY, VOLUME 50 

113998, CNHM 114110, 31.4-33.6 mm.) and Acandi (ANSP 164970, 
31.3-33.8 mm.) in Choc6, Colombia and the Rio Pucro, Dari£n, Pan- 
ama (ANSP 140505, 33.4 mm.), yet the smallest specimen, probably 
a dwarf, was from the Golfo de Uraba (Barker, 23.9 mm.). Slightly 
smaller than average specimens were seen from Chiriqui Lagoon, 
Bocas del Toro Island, and Rio Salud in Colon (see Table IX). A 
single specimen from Mona Creek, Almirante (ANSP 140304) was 
30.8 mm. in diameter, so it is not possible to postulate a clinal varia- 
tion in size from Colombia to Bocas del Toro. Few sets contained 
enough specimens to provide statistically significant data on varia- 
tion, and most of those were from El Valle. These sets were col- 
lected in 1936, 1938, 1958 and 1959. With the possible exception of 
those taken by Fairchild in 1958, all came from the restricted patch 
of woodland behind the Club Campestre at the foot of the cliffs. The 
Fairchild collection might have come either from the cliff top areas 
or from the same population as the other materials. The differences 
in measurements (Table IX) are obviously insignificant, indeed al- 
most unbelievably small. The length of life of L. unciger is unknown, 
but available collections cover at least two generations and indicate 
practically no variation in size, despite being from a habitat with 
extreme variations in annual rainfall patterns. 

Comparison of samples from different geographic areas does, in 
some cases, show significant size differences. The "t" test difference 
between shells from Bocas del Toro Island (ANSP 104303) and El 
Valle specimens (CNHM 63775) is highly significant for diameter and 
H/D ratio (n=18, t= 3.550 for diameter, £=3.6103 for H/D ratio), 
which is well below the 0.01 probability level. Other samples, such 
as chiriquiensis from Cerro Campana (MCZ) and Chiriqui Lagoon 
(ANSP 5612), do not differ significantly, having relatively high prob- 
abilities (0.20-0.50) of the variation being included in sampling error. 
More adequate collections are obviously needed before the extent and 
meaning of size variation can be judged. 

Labyrinthus creveauxianus (Ancey, 1890). Figures 27c-d, 28. 

Helix (Labyrinthus) uncigera var., Dohrn, 1875, Jahrb. deutsch. malacozool. 
Gesell., 2, pp. 297-298— Frontino, Colombia (Wallis!); Pilsbry, 1889, 
Man. Conch. (2), 5, p. 165. 

Helix creveauxiana Ancey, 1890, Bull. Soc. Malac. France, 7, p. 152 — Fron- 
tino, Colombia (based on Dohrn, loc. cit.). 

Caracolus (Labyrinthus) uncigera var. creveauxiana (Ancey), Pilsbry, 1892, 
Man. Conch. (2), 8, p. 264. 



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101 



102 FIELDIANA: ZOOLOGY, VOLUME 50 

Helix (Labyrinthus) uncigera frontinensis Kobelt, 1893, Syst. Conch. Cab., I 
(12), 4, p. 632, pi. 181, figs. 10-12 (plate issued in 1886). 

Range. — The only definite locality is Frontino, Antioquia, Co- 
lombia. 

Material.— Colombia: ANTIOQUIA— Frontino (Basel 432a— lec- 
totype and paratype, Edinburgh, CNHM 132551, paratypes). No 
exact locality; ANSP 8915, MCZ, Zurich ("Colombia"); CM 62.13580 
("Panama"); CNHM 248 ("Ecuador"). 

Diagnosis. — The prominent, sinuately twisted parietal lamella 
stops just before or barely joins the elevated parietal lip; parietal 
lip straight or with outer edge convex; basal lip slightly sinuated 
with thick, very prominent, crescentic lamellar tooth; lower palatal 
wall with a diagonally entering lamella, posteriorly with a hooked 
tooth nearly touching the lamella, strong inner lateral buttress; pe- 
riphery acutely angulated with protruding knife-edge keel; umbilicus 
only slightly obscured by basal and parietal lips; spire normally ele- 
vated, sides slightly rounded; color yellow-brown, lighter on keel, lip 
white, aperture darkly stained on palatal wall. Diameter 31.85- 
37.7 mm. (mean 35.5 mm.), H/D ratio 0.364-0.450 (mean 0.412). 

Remarks. — The uniform brown color, union of the parietal lamella 
with the more strongly raised and straight or convex parietal lip, high 
basal lamella with the hooked tooth and slightly larger size are the 
main characters separating creveauxianus from the closely related L. 
unciger (Petit) . The latter is common at low or medium elevations, 
while creveauxianus has been found only at the high country near 
Frontino. It may prove to be a montane derivative and could occur 
on the higher peaks of Dari£n in Panama, as seemingly does the bulim- 
ulid Sultana (Clathorthalicus) wallisi (Strebel). A single set in the 
Mousson collection labeled "Ocanna Wallis 1875" seems dubiously 
labeled. 

Variation in the lower palatal tooth is less extensive than in L. 
unciger. Most examples of L. creveauxianus had a simple hook, 
although in one example the tip almost touched the palatal wall. 
Some specimens seen had the tooth with moderately developed lateral 
buttresses. 

Group of Labyrinthus otis 

The four species are characterized by having the lower palatal 
tooth developed into a high transverse lamellar plate or conical, 
slanted ridge; a single basal tooth; a sinuately twisted parietal lamella 
that meets the parietal lip; and a carinated periphery. The condition 



SOLEM: NEOTROPICAL LAND SNAILS 103 

of the lower palatal tooth is the simplest in L. marmatensis, with the 
tooth a high conical or spade-shaped ridge that is only moderately 
recessed (see fig. 36e). In L. plicatus the broader, higher ridge has 
the basic form found in L. otis and L. subplanatus, but is not as large. 
In the latter two species the aperture is literally choked with the huge 
teeth and the snail has to undergo real contortions in withdrawing 
and extending its body through the armature. 

In contrast with species of the isodon and aenigmus groups, those 
of the otis complex have rather wide geographic ranges and show 
fairly extensive size variation. Two species, L. otis and L. subpla- 
natus, are divided into subspecies and also have overlapping distri- 
butions. The ranges of L. plicatus and L. marmatensis seem to be 
isolated from the others. Possibly L. euclausus Beddome, 1908 (see 
p. 125) also belongs to this complex. 

KEY TO THE LABYRINTHUS OTIS COMPLEX 

1. Lower palatal tooth nearly touching parietal lamella; basal lip usually markedly 

sinuated 2 

Lower palatal tooth separated from parietal lamella by a wide gap; basal lip 
nearly straight or weakly sinuated 6 

2. No deep supraperipheral sulcus on last one-quarter whorl 3 

Deep supraperipheral sulcus on last one-quarter whorl. 

Labyrinthus otis otis (Lightfoot, 1786) 

3. Periphery without strongly developed apertural notch 4 

Periphery with strongly developed apertural notch or spout 5 

4. Colombia; basal lip more strongly sinuated; basal and parietal lips dipping more 

into umbilicus Labyrinthus subplanatus subplanatus (Petit, 1843) 

Costa Rica and Panama; basal lip less sinuated; basal and parietal lips dipping 
less into umbilicus Labyrinthus otis orthorhinus Pilsbry, 1910 

5. Apertural notch at periphery turned slightly to strongly upward. 

Labyrinthus subplanatus erectus (Mousson, 1873) 
Apertural notch at periphery reflected up to form a rounded spout. 

Labyrinthus subplanatus sipunculatus (Forbes, 1850) 

6. Parietal lamella merging diagonally with parietal lip; Cauca River Valley. 

Labyrinthus marmatensis Pilsbry, 1910 
Parietal lamella merging almost perpendicularly with parietal lip ; Venezuela. 

Labyrinthus plicatus (Born, 1780) 

Differences between some of the forms recognized as subspecies of 
different species are rather subtle and difficult to present adequately 
in keys. Where species and subspecies could be confused, the non- 
overlapping geographic ranges (fig. 59) enable easy separation. For 
convenience, brief diagnoses of the species are presented here, as well 
as the more expanded diagnoses under each nomenclatural unit. 



104 FIELDIANA: ZOOLOGY, VOLUME 50 

L. marmatensis Pilsbry, 1910 — small shells (diameter 32 mm.) 
with nearly straight basal lip, small teeth, flat spire (mean H/D ratio 
0.363) and the parietal lamella merging diagonally with the parietal 
lip (fig. 36e). Caldas and Antioquia in Colombia. 

L. plicatus (Born, 1780) — much larger shells (diameter 36-53 mm.) 
with straight basal lip, small teeth, higher spire (H/D ratio 0.405- 
0.450), and parietal lamella meeting parietal lip perpendicularly. 
Aragua, Carabobo, Yaracuy and Falcon in Venezuela. 

L. otis (Lightfoot, 1786) — large shells (diameter 34-58 mm.) with 
massive teeth choking the aperture, strongly sinuated parietal and 
basal lip and, in the Colombian subspecies, a very conspicuous, deep 
supraperipheral groove on the last one-quarter of the body whorl. 
Cundinamarca, Santander, Bolivar, Antioquia and Choco in Colom- 
bia, north through Panama to Veraguas and Cocle\ then as a prob- 
ably relict population in the Golfo Dulce region of Costa Rica. 

L. subplanatus (Petit, 1843) — smaller shells (diameter 34-45 mm.) 
with weak supraperipheral groove, very strongly sinuated basal lip, 
and in one subspecies, the peripheral notch reflected upward to form 
a spout. A disjunctive distribution in Colombia, with the nominate 
race extending from Norte de Santander to Cundinamarca in the 
Cordillera Oriental and one record from Caldas in the Cordillera Cen- 
tral; two subspecies ranging from Valle de Cauca north through 
Choc6 and Dari£n as far as Cerro Campana, Panama Province, 
Panama. 

Considerable confusion existed in the older literature concerning 
the identity of the names proposed for these forms and their relation- 
ships. The original illustrations can be interpreted many ways and 
the original specimens of all but L. plicatus are doubtfully extant. 
It is thus far simpler to accept Deshayes (1838) clear separation of 
L. plicatus and L. otis than to worry about ancient citations. Dr. 
O. Paget has kindly informed me that the original specimens of L. 
plicatus (Born, 1780) are still preserved in Vienna and the species is 
correctly identified. L. otis and L. subplanatus have continually been 
confused, mostly because of lack of detailed locality records. L. sub- 
planatus is very similar to the Panamanian L. otis orthorhinus, differ- 
ing primarily by its more sinuated basal lip and less acutely carinated 
shell. L. otis otis differs strikingly from L. subplanatus in having the 
deep supraperipheral groove and in being much larger. The latter 
two have not been collected at the same locality and their ranges are 
only partly overlapping. 



SOLEM: NEOTROPICAL LAND SNAILS 105 

Labyrinthus otis (Lightfoot, 1786) 

The specific name has normally been credited to Daniel Solander, 
but Dance (1962) has shown that the anonymous Portland Catalogue 
should be attributed to the Rev. John Lightfoot. 

The species is easily divisible into two subspecies: 
L. otis otis (Lightfoot, 1786) — last quarter of body whorl with a 
deep, narrow supraperipheral groove, parietal lip strongly sinuated, 
inner margin running parallel or nearly parallel with the inner margin 
of the basal lip. Rather widely distributed in Cundinamarca, San- 
tander, Bolivar, Antioquia and Choc6. 

L. otis orthorhinus Pilsbry, 1910 — supraperipheral groove very 
faint or at most broad and shallow, parietal lip not as strongly sinu- 
ated and rarely parallel to the basal lip margin. Found from the 
Colombian-Panamanian border to El Valle, Code' and the Azuero 
Peninsula region of Veraguas, then in San Jos£, Costa Rica. 

No obviously intermediate examples are known, but so little col- 
lecting has been done in Choc6 and Dari£n that this is not surprising. 

Labyrinthus otis otis (Lightfoot, 1786). Figures 30a-b, 31b. 

Favanne, 1780, La Conchyliologie, pi. 63, fig. F 11. 

Helix otis Lightfoot, 1786, A catalogue of the Portland Museum . . ., p. 38, 
lot No. 925 and p. 53, No. 1260 (based on Favanne, loc. cit.). 

Helix labyrinthus Chemnitz, 1795, Syst. Conch. Cab., ed. 1, 11, pp. 271-272, 
pi. 208, fig. 2048 (copied from Favanne) 1 ; Deshayes, 1838, Guerin's Mag. 
de Zool., 1838, pi. Ill, fig. 1— Panama; Pfeiffer, 1847, Syst. Conch. Cab., 
2nd ed., I (12), 1, p. 61, pi. 2, fig. 5 (copy of figure in first edition); De- 
shayes, 1851, Hist. Nat. Moll., 1, pp. 388-390, pi. 54B, fig. 5 (plate issued 
in 1823); Pfeiffer, 1852, Syst. Conch. Cab., I (12), 2, p. 205; Reeve, 1852, 
Conch. Icon., Helix, pi. 100, fig. 550 — Central America. 

Helix (Labyrinthus) labyrinthus Deshayes, Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 161-163 (partly), pi. 39, figs. 87-90. 

Labyrinthus plicatus Martens, 1893 (not Born, 1780), Biol. Centr. Amer., 
Moll., p. 177. 

Pleurodonte (Labyrinthus) labyrinthus (Deshayes), Pilsbry, 1894, Man. Conch. 
(2), 9, p. 95. 

Pleurodonte (Labyrinthus) otis (Solander), Pilsbry, 1910, Proc. Acad. Nat. Sci., 
Philadelphia, 1910, p. 504, pi. 37, figs. 5-7; Pilsbry, 1926, op. cit., 78, 
pp. 74-75— Cartagena (Lloyd B. Smith!). 

Range. — Colombia: Cundinamarca, Santander, Bolivar, Antio- 
quia, Choc6. 

1 Ruled a non-binomial work by Opinion 184 of the International Commission 
on Zoological Nomenclature. 



106 FIELDIANA: ZOOLOGY, VOLUME 50 

Material— Colombia: CUN DIN AM ARC A (Zurich)— Montere- 
dondo at km. 76 on road from Bogota to Villavicencio (CNHM 
113995, CNHM 113996). SANTANDER— 45 miles southeast of 
Barrancabermeja (USNM 341476). BOLIVAR— Quebrada Salva- 
jin, Rio Esmerelda, Upper Rio Sinu (USNM 601776); Upper Rio 
Ure\ Rio San Jorge (CNHM 133263) ; Limon, west of Monteria, Rio 
Sinu (USNM 364339) ; road between Rio San Jorge and Palmaviral 
(ANSP 160144, MCZ 95722); La Burra (R. Wright Barker); La 
Union (CNHM 117527); Rio Canalete, y 2 mile above La Union 
(USNM 364338); near Cartagena (ANSP 111651, CM 62.39790). 
ANTIOQUIA— Turbo and Le6n Valley to the south (USNM 543479, 
CNHM 71045); Gulf of Uraba (R. Wright Barker, Basel 5432a); 
Punta Piedras, near Nicoli, Gulf of Uraba (CNHM 113925). CHOCO 
-15 km. inland, Rio Nuqui (USNM 488859) ; between Puerta Ardita 
and Cored6 (CNHM 113888). 

Diagnosis. — The high, sinuated parietal lamella merges diagonally 
with the parietal lip; basal lip slightly sinuated with single, thick, 
twisted lamella; lower palatal lip nearly straight with huge trans- 
verse, diagonal lamellar tooth nearly touching parietal lamella; pe- 
riphery with narrow notch slightly reflected upward, last one-quarter 
of body whorl with deep supraperipheral sulcus; upper palatal lip 
with recessed crescentic lamella above upper edge of lower palatal 
tooth; parietal and basal lips usually run parallel into umbilicus; 
spire normally elevated, rounded above; color dark yellow brown. 
Diameter 39-54 mm., H/D ratio 0.400-0.483. 

Remarks. — The very pronounced supraperipheral groove on the 
last one-quarter whorl and the tendency of the umbilical extension 
to narrow with the parietal and basal lips running parallel are the 
diagnostic characters. No specimens intergrading between otis and 
orthorhinus were seen, but probably will be collected eventually in 
southern Dari£n or the Atrato River basin. 

Most of the specimens were between 45 and 54 mm. in diameter. 
In only a few cases were more than single shells seen from any one 
locality. Variability in these sets is covered in Table X. Sets from 
Choc6, Bolivar and Antioquia averaged 50.1, 47.7 and 47.4 mm. in 
diameter. These differences are significant at the 0.05 probability 
level when either of the smaller is compared with the larger, but the 
differences between the two smaller are not significant. A single 
specimen from Monteredondo is much smaller (diameter 41.6 mm.) 
and a dwarfed population from near Cartagena averaged 39.5 mm. 



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108 FIELDIANA: ZOOLOGY, VOLUME 50 

The single adult from the Upper Rio lire" (CNHM 133263) was 
collected on January 31, 1963. That evening it laid a cluster of eight 
whitish, globular eggs which, when preserved, measured 4.4-4.9 mm. 
in diameter. Unfortunately, the soft parts of the adult were not 
preserved. 

Labyrinthus otis orthorhinus Pilsbry, 1910. Figures 30c-d, 31a. 

Helix plicata Tate, 1866 (not Born, 1780), Amer. Jour. Conch., 5, p. 156 — 
north shore of Naval Bay, Col6n, Panama. 

Helix labyrinthus Deshayes, Pilsbry, 1889, Man. Conch. (2), 5, pp. 161-163 
(partly), pi. 64, figs. 14-16 (from Gorgona, Canal Zone). 

Pleurodonte (Labyrinthus) labyrinthus Pilsbry, 1894, op. cit., 9, pi. 25, figs. 4-5. 

Pleurodonte (Labyrinthus) plicata Dall, 1909 (not Born, 1780), Smith. Misc. 
Coll., 52 (3), p. 361— Atrato River, "Sierra Darien" (A. E. Heighway!). 

Pleurodonte (Labyrinthus) otis orthorhinus Pilsbry, 1910, Proc. Acad. Nat. Sci., 
Philadelphia, 1910, pp. 502, 505, pi. 37, figs. 1-4— between Tabernillo and 
San Pablo, Canal Zone, Panama (Amos P. Brown!); Pilsbry, 1926, op. cit., 
78, p. 75 — near Gatun Dam, Canal Zone (A. A. Olsson!); near Darien and 
Alhajuela, Canal Zone (J. Zetek!); Quipo (=Cuipo), Colon (J. P. Chapin!); 
Upper Chagres (J. Zetek!); Pilsbry, 1930, op. cit., 82, p. 339— Barro Colo- 
rado Island, Canal Zone; hills near Mandingo River, head of Gulf of San 
Bias, Comarca de San Bias (Pilsbry!). 

Pleurodonte labyrinthus Dall, 1912 (not Deshayes, 1838), Smith. Misc. Coll., 
59 (18), p. 1, pi. 2, figs. 3-4— Santa Isabel, Colon (Pittier!). 

Range. — Vicinity of Panamanian-Colombian border north to 
Golfo Dulce region of Costa Rica. Possibly absent from Chiriqui 
and Bocas del Toro, the Costa Rican populations being relicts. 

Material. — Colombia: CHOCO — mountains near mouth of Atrato 
River (USNM 206288) ; Acandi (ANSP 150244). Panama: DARIEN 
— Pintupo (ANSP 161811; Tacarcuna (MCZ 247232). COMARCA 
DE SAN BLAS— forest near Armila (USNM 228664); hills near 
Mandingo River, head of Gulf of San Bias (ANSP 151397, ANSP 
243693). PANAMA — mountains around Gaspasalana, high Ma- 
moni River (USNM 228907); between Chepo and Rio Platanal 
(ANSP 162480); Rio Indio, near Madden Lake (CNHM 20611); 
along ridge of Rio Chico, fork of Rio Pequeni and Rio Boquer6n 
(ANSP 155410); La Aneida, near Tocumen Airport, 9 km. from 
Cerro Azul (CNHM 117035) ; slope of Cerro Cabra (ANSP 162486); 
hills above Arraijan (CNHM 125388); Cerro Trinidad (CNHM 
117552, CNHM 132541); Cerro Campana (CNHM 73363, MCZ, 
USNM 596734). CANAL ZONE— between Tabernillo and San 
Pablo (ANSP 101306, ANSP 101308, CNHM 78829); near Empire 
(MCZ 45143); near Gorgona (MCZ 154015, ANSP 8907); Alhajuela 







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SOLEM: NEOTROPICAL LAND SNAILS 111 

(USNM 228665, USNM 251432, ANSP 162478); Gatun (USNM 
251424, USNM 360669); Barro Colorado Island (numerous sets); 
Salamanca Hydrographic Station, Rio Pequeni (MCZ 111166, Jack- 
son 4828); shore of Madden Lake (CNHM 73365, CNHM 73431, 





Fig. 31. Supraperipheral grooves in: a, Labyrinthus o. orthorhinus; b, Laby- 
rinthus o. otis. 

CNHM 84465, CNHM 125379, USNM 589728). COLON— Santa 
Isabel (USNM 228663) ; Quebrada Querquera, 15 miles NE of Colon 
(USNM 601014); near Cuipo (CNHM 63772, CNHM 63773); San 
Juanito, near Pegero, Code" del Norte (USNM 618835). COCLE- 
El Valle (CNHM 63770, CNHM 73372, MCZ 88936, USNM 596735, 
ANSP 226920). VERAGUAS— (all in Azuero Peninsula area, col- 
lected by E. R. Dunn in 1940) Tres Punta (ANSP 184697) ; Avacada 
Camp at 2,100 feet elevation (ANSP 184696); Mangillo (ANSP 
184698). Costa Rica: SAN JOSE— Santa Maria de Dota at 1,500 
meters elevation (USNM 363817). 

Diagnosis. — The high, sinuately twisted parietal lamella usually 
merges perpendicularly with the parietal lip; basal lip slightly sinu- 
ated with single thick, crescentic lamella; lower palatal lip with high, 
diagonally spade-shaped lamellar tooth nearly touching parietal la- 
mella; periphery with faint internal groove, but no notch and only 
a faint supraperipheral sulcus on body whorl; upper palatal lip with 
a small to medium sized, crescentic lamella, recessed and above lower 
palatal tooth; parietal and basal lips usually not running parallel and 
only weakly dipping into umbilicus; spire normally elevated, sides 
flat or rounded above; color dark reddish or yellow brown. Diam- 
eter 34-58.5 mm., H/D ratio 0.350-0.476. 



112 FIELDIANA: ZOOLOGY, VOLUME 50 

Remarks. — The usually perpendicular insertion of the parietal la- 
mella on the parietal lip, lack of a supraperipheral sulcus and less 
deep penetration of the basal and parietal lips into the umbilicus 
easily separate L. o. orthorhinus from the nominate subspecies. Ade- 
quate collections may show that these are non-intergrading allopatric 
populations, but variability in the observed material suggests that 
they will be shown to be subspecialty related morphs. 

Comparatively simple variation is shown in most populations of 
this species. Shells from wetter areas are significantly larger than 
those from drier zones, areas such as Cerro Cabra near the Pacific 
Coast having dwarfed specimens (diameter 39.1-39.6 mm.) while 
those from Gatun (mean diameter 44.6 mm.) or Armita (mean diam- 
eter 44.5 mm.) are significantly larger. Size variation in a number of 
populations is summarized in Tables X and XL 

The few examples known from Cerro Campana, El Valle and Co- 
de 1 del Norte, are, with three exceptions, extremely large, ranging 
from 48.7-58.5 mm. in diameter. James Zetek had two shells labeled 
"El Valle" that are only 36.6-37.1 mm. in diameter, while one speci- 
men from Cerro Campana was only 43.9 mm. in diameter. The 
Zetek shells might have been mislabeled. The specimens from Cerro 
Trinidad (CNHM 132541) are somewhat smaller (mean diameter 
48.8 mm.), but well above the size of most Canal Zone populations. 
Samples from Pintupo, Darien (mean diameter 49.8 mm.), La Aneida 
near Cerro Azul (47.3 mm.), Salamanca Hydrographic Station (47.8 
mm.), and Gatun (44.6 mm.) are also rather large. Material from 
Tacarcuna, Darien (40.9 mm.), Gorgona, Canal Zone (42.4 mm.) and 
the types from between Tabernillo and San Pablo (41.6 mm.) are 
distinctly smaller. 

Apparently the Barro Colorado Island population is dwarfed. 
Dated sets from 1930, 1936 and 1959 plus several undated series all 
showed mean diameters of 37.4-38.4 mm. No collections from adja- 
cent mainland areas have been made and it is unknown if the Barro 
Colorado Island specimens are exceptionally dwarfed or merely repre- 
sentative of equally dwarfed populations in the general region. 
"Small island" dwarfed populations of land snail species are known, 
but the situation of the Barro Colorado Island shells remains to be 
investigated. It is known that Barro Colorado has an exceedingly 
heavy population of coatis. These occasionally eat L. otis orthorhinus 
(Kaufmann, 1962, p. 183). The coati has a very difficult time crack- 
ing the shell and usually depends on other food sources (personal 
communication from Dr. Kaufmann). Despite this, the possibility 



SOLEM: NEOTROPICAL LAND SNAILS 113 

must be considered that the coatis provide a selective pressure for 
smaller size, since individuals less able to retreat into narrow crevices 
are more apt to be eaten. Even casual observation of foraging coatis 
brings forth great admiration for the thoroughness of their inspection 
of forest floor niches. 

Most living specimens of L. otis orthorhinus have been taken near 
or under large fallen logs in at least moderately heavy forest. They 
aestivate in cracks in old logs and under logs and starting bark on 
the ground. During the very dry January of 1959 on Barro Colorado 
Island no living specimens were obtained. The wetter areas near 
Madden Lake in February of the same year yielded live specimens 
under hanging sheets of bark on old stumps at 5-7 feet above ground 
level. The strong development of the parietal and lower palatal 
teeth results in their nearly touching. Retraction and extension of 
the animal does not seem to be slowed by the large armature, but it 
does force the animal to retract and extend solely through the narrow 
passage between the parietal wall and basal lip. Observation of the 
exact process was difficult, but it appears that expansion is virtually 
complete before the thin roof of the pallial cavity is extended through 
the gap between the parietal and lower palatal lamellae. The mus- 
cular mantle collar has been extended past this point and thus does 
not have to squeeze between. The collar and pallial wall is then 
appressed to the upper and outer lip edges. The reverse process 
occurs on retraction. 

Labyrinthus subplanatus (Petit, 1843) 
This smaller relative of L. otis is divided into three subspecies, 
one of which ranges into Central Panama. An isolated subspecies, 
L. s. subplanatus, is exceedingly similar to some specimens of the 
Panamanian L. otis orthorhinus. Conceivably, subplanatus, s.s., could 
be a direct offshoot of typical otis, but the two have been found in the 
same region. For this reason and the presence of near intergrades I 
have chosen to associate it with the Western Colombian and Pana- 
manian populations. No form of subplanatus has been dissected and 
only the orthorhinus form of otis is known anatomically. 

The three subspecies of L. subplanatus can be separated as follows: 

L. subplanatus subplanatus (Petit, 1843) — color light brown to 

speckled, basal lip moderately sinuated, peripheral notch a slight 

groove not twisted upward, size 34-45 mm. Caldas and Cundina- 

marca to Norte de Santander. 

L. subplanatus erectus (Mousson, 1873) — color brown or speckled 
brown, basal lip sharply sinuated, peripheral notch slightly twisted 



114 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 32. Apertures in: a, Labyrinthus s. subplanatus, San Juan de Dios and 
San Juan del Silencio, Santander, Colombia. R. Wright Barker; b, Labyrinthus 
s. eredus, between Buenaventura and Rio Calima, Valle de Cauca, Colombia, 
CNHM 113999; c, Labyrinthus s. eredus, Bogota, Colombia. Zurich. Holotype; d, 
Labyrinthus plicatus, normal form, "Venezuela." Zurich. Scale line equals 10 mm. 



upward, size 31-38 mm. Valle de Cauca, Antioquia, and Choco, 
possibly Cundinamarca. 

L. subplanatus sipunculatus (Forbes, 1850) — color light brown to 
reddish brown with yellow-white periphery, basal lip sharply sinu- 
ated, peripheral notch twisted sharply upward to form a spout, size 
34-42 mm. Central Choco to Panama Province, Panama. 



Labyrinthus subplanatus subplanatus (Petit, 1843). Figures 

Carocolla subplanata Petit, 1843, Rev. Zool., 1843, p. 238 — New Granada 

(= Colombia); Petit, 1843, Guerin's Mag. de Zool., 1843, pi. 68. 
Helix labyrinthus var. Pfeiffer, 1848, Monog. helic. viv., 1, p. 398; Pfeiffer, 1852, 

Syst. Conch. Cab., I (12), 2, pp. 205-206, pi. 104, figs. 5-7 (plate issued 

in 1850). 
Helix (Labyrinthus) subplanatus (Petit), Dohrn, 1875, Jahrb. deutsch. malac. 

Gesell., 2, pp. 296-297. 






SOLEM: NEOTROPICAL LAND SNAILS 



115 







Fig. 33. Shells of: a, Labyrinthus s. subplanatus, San Juan de Dios and San 
Juan del Silencio, Santander, Colombia. R. Wright Barker; b, Labyrinthus s. si- 
punculatus, Finca "La Victoria," Rio Baudo, Colombia, CNHM 113994; c, Laby- 
rinthus s. erectus, between Buenaventura and Rio Calima, Valle de Cauca, Colom- 
bia, CNHM 113999; d-f, Labyrinthus s. erectus, Bogota, Colombia. Zurich. 
Holotype (d, side; e, top;/, base). Scale line equals 10 mm. 



Helix (Labyrinthus) labyrinthus Deshayes, Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 161-163, pi. 40, figs. 100-102 (partly). 

Pleurodonte (Labyrinthus) otis subplanatus (Petit), Pilsbry, 1910, Proc. Acad. 
Nat. Sci., Philadelphia, 1910, p. 504. 

Range. — Cordillera Oriental of Colombia in Santander and Cun- 
dinamarca; Cordillera Central in Caldas. Possibly Sierra de Perija 
in Norte de Santander. 



116 FIELDIANA: ZOOLOGY, VOLUME 50 

Material— Colombia: NORTE DE SANTANDER— Ocana (Zur- 
ich) ; Mt. Alto de la Cruz, Ocana (Zurich) ; dense jungle, 13 km. south 
of Puerto Santos (USNM 380794). SANTANDER— near Rio Sucio 
at 600-800 feet elevation (USNM 363924) ; Rio Lebrija valley at 
1,000 feet elevation (USNM 601777); Rios San Juan de Dios and 
San Juan del Silencio, Carere (R. Wright Barker) ; south part of San- 
tander (USNM 472800, CNHM 71044); Landazuri at 830 meters 
elevation (MCZ 179595). CALDAS— Victoria at 820 meters eleva- 
tion (CNHM 113997). 

Diagnosis. — The very prominent, sinuately twisted parietal la- 
mella runs almost perpendicularly into the raised parietal lip; basal 
lip moderately to strongly sinuated, with very thick slanted lamella; 
periphery acutely angulated with protruding keel, small groove inside 
aperture, no deep supraperipheral sulcus; upper palatal lip with low, 
deeply recessed crescentic lamella located above apex of lower palatal 
tooth; basal and parietal lips dipping moderately deeply into umbili- 
cus; spire generally strongly elevated, rounded above; color dark 
brown to speckled with greenish-yellow. Diameter 34.6-44.6 mm. 
(mean 38.3 mm.), H/D ratio 0.384-0.502 (mean 0.440). 

Remarks. — The absence of a strong supraperipheral sulcus and 
the more nearly perpendicular insertion of the parietal lamella into 
the parietal lip are the main characters separating subplanatus from 
otis otis. L. otis orthorhinus is less readily distinguished, the differ- 
ences from subplanatus of less sinuated basal lip and shallow dipping 
of the basal and parietal lips into the umbilicus being of degree. The 
ranges of subplanatus and otis orthorhinus are widely separated, so 
that there is little chance of confusion. Both L. otis otis and L. sub- 
planatus have been reported from the same general areas, but not 
from the same locality. 

Most specimens of L. subplanatus were 36-40 mm. in diameter. 
The single shell from Caldas was 41.5 mm. and the Landazuri exam- 
ple 44.6 mm. The diameter of the type was given as 40 mm. and the 
dark brown shell is matched by several specimens from Santander. 
Several examples were the greenish-speckled brown of L. s. erectus, 
but differ very slightly in having a less sinuated lip and no real re- 
flection of the peripheral notch. 

Labyrinthus subplanatus erectus (Mousson, 1873). Figures 
32b-c, 33c-f. 

Helix erecta Mousson, 1873, Malak. Blatt., 21, pp. 3-4 — Bogota, Colombia 
(Wallis!); Pfeiffer, 1876, Novit. Conch., 4, pp. 116-117, pi. 127, figs. 1-3; 



SOLEM: NEOTROPICAL LAND SNAILS 117 

Pfeiffer, 1876, Monog. helic. viv., 7, p. 461; Pilsbry, 1889, Man. Conch. 
(2), 5, p. 162, pi. 40, figs. 100-102. 

Pleurodonte (Labyrinthus) otis erecta (Mousson), Pilsbry, 1910, Proc. Acad. 
Nat. Sci., Philadelphia, 1910, p. 505. 

Range. — Choco and Valle de Cauca in Western Colombia, pos- 
sibly Cundinamarca. 

Material— Colombia: CUNDINAMARCA— Bogota (Zurich, 
types). VALLE DE CAUCA — region between Buenaventura and 
Rio Calima (CNHM 113999, CNHM 117525); Anchicaya, between 
Cali and Buenaventura at 300-500 meters (SMF 162665) ; La Brea 
Calima, Municipio Buenaventura (MCZ 177962). CHOCO— Rio 
Atrato (R. Wright Barker, CNHM 117526); 15 km. inland, Rio Nu- 
qui (USNM 488860). ANTIOQUIA— Frontino (Zurich). "Ecua- 
dor" (CNHM 40774). 

Diagnosis. — The very high, sinuately twisted parietal lamella 
slants diagonally into the elevated parietal lip; basal lip strongly 
sinuated, with thick, slanted lamella; lower palatal lip nearly straight 
with very high transverse lamella; periphery acutely angulated with 
protruding knife-edge keel, peripheral notch distinctly reflected up- 
ward, no prominent supraperipheral sulcus; upper palatal lip with 
small crescentic lamella, deeply recessed, placed above apex of lower 
palatal tooth; basal and parietal lips dipping deeply into umbilicus; 
spire moderately elevated, sides flat or rounded above; color brown- 
ish, speckled with greenish-yellow flecks. Diameter 31.2-38.1 mm. 
(mean 34.2 mm.), H/D ratio 0.400-0.450 (mean 0.423). 

Remarks. — The more sinuated basal lip, more angulated junction 
of the parietal lamella and lip, greater reflection upward of the pe- 
ripheral notch and usually smaller size separate typical examples of 
L. s. erectus from L. s. subplanatus. Too little material is available 
to allow delineation of ranges or to show intergradation. The original 
locality of "Bogota" is obviously of little meaning. Neither of the 
two specimens in the Mousson collection matches Pfeiffer's illustra- 
tion (loc. cit.) or the dimensions given in the original description. 
The present locality of the Pfeiffer collection is unknown. Since 
Mousson could have been presumed to retain possession of good ex- 
amples, I have chosen as lectotype the better preserved of the two 
cotypes (fig. 33d-f) . The specimen is 31.2 mm. in diameter, 13.0 mm. 
high with slightly more than 4% whorls. The material from Choc6 
and Valle de Cauca is distinctly larger than the types, but the single 
shell from Frontino is also small. Further collecting may show that 



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SOLEM: NEOTROPICAL LAND SNAILS 119 

the type locality is an error and that erectus is found only in the 
Atrato, San Juan and Calima river basins. 

Intergradation between erectus and sipunculatus is present in a 
set collected in February, 1951 in a forest near Nuqui, Dept. Choc6 
(USNM 596996) . The four specimens range from the typical spout 
of sipunculatus to a notch only slightly more developed than in typ- 
ical erectus (see fig. 35). 

Labyrinthus subplanatus sipunculatus (Forbes, 1850). Figures 
33b, 34a, 35. 

Helix labyrinthus var. sipunculatus Forbes, 1850, Proc. Zool. Soc. London, 

1850, p. 53, pi. 9, figs. 4a, b — Panama. 
Helix annulifera Pfeiffer, 1852, Conch. Icon., Helix, pi. 100, fig. 555 — Central 

America; Pfeiffer, 1853, Proc. Zool. Soc. London, 1851, p. 260 — Panama; 

Pfeiffer, 1853, Monog. helic. viv., 3, p. 255. 

Helix (Labyrinthus) labyrinthus var. annulifera Pfeiffer, Pilsbry, 1889, Man. 

Conch. (2), 5, p. 162, pi. 42, figs. 32-33. 
Labyrinthus annuliferus (Pfeiffer), Martens, 1893, Biol. Centr. Amer., Moll., 

p. 177. 
Pleurodonte (Labyrinthus) otis sipunculala (Forbes), Pilsbry, 1910, Proc. Acad. 

Nat. Sci., Philadelphia, 1910, p. 504. 
Pleurodonte (Labyrinthus) otis annulifera (Pfeiffer), Pilsbry, 1910, op. cit., 

1910, pp. 504-505. 
Pleurodonte (Labyrinthus) goldmani Dall, 1912, Smith. Misc. Coll., 59 (18), 

pp. 1-2, pi. 2, figs. 1-2 — Pirri Range, Darien, Panama (E. A. Goldman!). 

Pleurodonte (Labyrinthus) sipunculata (Forbes), Pilsbry, 1926, Proc. Acad. 

Nat. Sci., Philadelphia, 78, p. 74, pi. 9, fig. 4— Paya and Rio Tucuti. 

Darien, Panama (A. A. Olsson!). 
Pleurodonte (Labyrinthus) sipunculata annulifera (Pfeiffer), Pilsbry, 1926, op. 

cit., 78, p. 74. 

Range.— Rio Baudo and Nuqui, Choc6, Colombia north to Cerro 
Campana, Panama Prov., Panama. 

Material. — Colombia: CHOCO — Finca La Victoria, boca del Pepe, 
Rio Baudo (CNHM 113994); Nuqui in forest (USNM 596996); 
mountains near mouth of Atrato River (USNM 206289). Panama: 
DARlfiN— Pirri Range (USNM 214403, USNM 622080 types of 
goldmani) ; Paya (ANSP 140306) ; Rio Tucuti (ANSP 140307). PAN- 
AMA— Cerro Campana (MCZ); Serra Chucanti at 1,800 feet eleva- 
tion (USNM 620477). "Ecuador" (Zurich). 

Diagnosis. — The high, sinuately twisted parietal lamella merges 
diagonally with the raised parietal lip; basal lip very strongly sinu- 
ated with thick, twisted lamellar tooth; lower palatal lip nearly 



120 



FIELDIANA: ZOOLOGY, VOLUME 50 





Fig. 34. Apertures of: a, Labyrinthus s. sipunculatus, Finca "La Victoria," 
Rio Baudo, Colombia, CNHM 113994; b, Labyrinthus plicatus, heavy form, "Vene- 
zuela." Zurich. Scale lines equal 10 mm. 



straight with very high transverse lamella; periphery acutely angu- 
lated with somewhat protruding keel, periphery with notch turned 
upward, connected by narrow groove to rest of aperture, no marked 
supraperipheral sulcus; upper palatal lip with low, deeply recessed 
crescentic lamella located above apex of lower palatal tooth; basal 
and parietal lips extending into umbilicus; spire strongly elevated, 
sides flat; color dark yellow brown to reddish brown with lighter pe- 













Fig. 35. Variation of peripheral notch in: Labyrinthus s. sipunculatus, Rfo 
Nuqui, Choco, Colombia, USNM 596996. 



121 



122 FIELDIANA: ZOOLOGY, VOLUME 50 

ripheral zone. Diameter 33.9-42.4 mm. (mean 37.4 mm.), H/D ratio 
0.360-0.464 (mean 0.411). 

Remarks. — The extreme sinuosity of the basal lip and the upward 
reflection of the peripheral notch to form a spout are the main identi- 
fying characters. The specimens from Nuqui (see fig. 35) inter- 
grade with erectus, and color variation connects the pale brown 
sipunculatus and the reddish-brown zoned annuliferus. The speci- 
mens on which goldmani Dall, 1912 was based are simply larger indi- 
viduals of sipunculatus. Variation in two sets is summarized in 
Table XII. The record from Cerro Campana is rather surprising. 
Despite the very considerable collecting in the vicinity of the Canal 
Zone, no specimens of sipunculatus have been found between Cerro 
Campana and the Rio Tucuti. The specimens could have been mis- 
labeled, but it is equally probable that the Cerro Campana shells 
came from a relict population. 

Labyrinthus plicatus (Born, 1780). Figures 32d, 34b, 36a. 

Helix plicata Born, 1780, Test. Musei Caesarei Vindobonensis, p. 368 — East 
Indies (error). Based on Knorr, 1771, Vergnugen der Augen und des 
Gemiiths, pt. V, pi. 26, fig. 5; Deshayes, 1838, Guerin's Mag. de Zool., 
pi. 110; Deshayes, 1851, Hist. Nat. Moll., 1, pp. 387-388, pi. 54B, fig. 4; 
Pfeiffer, 1852, Syst. Conch. Cab., I (12), 2, pp. 204-205, pi. 104, figs. 1-4 
(plate issued in 1850); Reeve, 1852, Conch. Icon., Helix, pi. 100, figs. 
553a-b. 

Helix labyrinthus Lamarck, 1792, Jour. d'Hist. Nat., 2, p. 352, pi. 42, fig. 4. 

Carocolla hydiana Lea, 1838, Obs. Genus Unio, 2, p. 98, pi. 23, fig. 73 — near 
Puerto Cabello, Venezuela. 

Helix (Labyrinthus) plicatus (Born), von Martens, 1873, Ges. Naturf. Fr. Ber- 
lin, Festschr., 1873, p. 168 — Puerto Cabello, Chino, Caracas, Venezuela; 
Pilsbry, 1889, Man. Conch. (2), 5, pp. 163-164, pi. 63, figs. 1-5, 9. 

Pleurodonte (Labyrinthus) plicata (Born), Pilsbry, 1894, Man. Conch. (2), 9, 
p. 95; H. B. Baker, 1926, Occ. Pap. Univ. Michigan Mus. Zool., 167, 
pp. 16-19, pi. 12, figs. 65-67, pi. 14, fig. 73— San Esteban Valley below 
Los Quiguas, Carabobo; Banco Largo near Bejuma, Carabobo; Palma 
Sola, Yaracuy; Quebrada Sucremo, Boqueron, Yaracuy. 

Labyrinthus plicatus (Born), Wurtz, 1955, Proc. Acad. Nat. Sci., Philadelphia, 
108, pp. 113-117; Thompson, 1957, Occ. Pap. Univ. Michigan Mus. Zool., 
591, p. 5 — Rancho Grande, Aragua, Falcon, Venezuela. 

Range. — Venezuela: Aragua, Carabobo, Yaracuy, Falcon. 

Material. — Venezuela: FALCON — El Mene and Riecito, Acosta 
(CNHM 71043, USNM 508782, USNM 499989, MCZ 64951); To- 
cuyo Valley, between Guaidima and Taparito (MCZ 115523) ; Pauji, 
Acosta (MCZ 154932). CARABOBO— Puerto Cabello (CM 62.- 






SOLEM: NEOTROPICAL LAND SNAILS 123 

12727); near Puerto Cabello (USNM 106002, ANSP 8910, ANSP 
8912, types of hydiana Lea, MCZ 88156, MCZ 154016) ; 6 miles west 
of Puerto Cabello (USNM 214443); Chorim, Puerto Cabello (ANSP 
8911); La Guaira (USNM 307393); Manuare (MCZ 172026). DIS- 
TRICTO FEDERALES— Catuche, Caracas (USNM 252689). 
YARACUY— Palma Sola (ANSP 138643, MCZ 63047). ARAGUA 
— Rancho Grande (MCZ 210889, SMF 181617). 

Diagnosis. — The high, sinuated parietal lamella usually merges 
perpendicularly with the parietal lip; basal lip straight with a single 
thick, diagonally slanted tooth; lower palatal lip with large spade- 
shaped, diagonal lamella whose upper edge is well separated from the 
parietal lamella; periphery with internal groove, but no notch or 
supraperipheral sulcus; upper palatal wall with or without trace of 
a recessed, crescentic lamella above top edge of lower palatal tooth; 
parietal and basal lips only slightly dipping into umbilicus; spire nor- 
mally elevated, rounded above; color yellow brown. Diameter 36- 
53 mm., H/D ratio 0.376-0.505. 

Remarks. — Typical specimens .show a greatly reduced dentition 
from that seen in subplanatus or otis orthorhinus. The lower palatal 
tooth is only a fraction of the size found in the preceding forms and 
there is a large spatial gap between the parietal and lower palatal 
lamellae. L. otis otis immediately differs in having the very strong 
supraperipheral sulcus on the last one-quarter whorl. The much 
smaller L. marmatensis differs in having the parietal lamella diago- 
nally merging with the parietal lip, while in plicatus the parietal la- 
mella inserts almost perpendicularly into the parietal lip (see figs. 
34b, 36e). 

The types of Carocolla hydiana Lea, 1838 (USNM 106002) are 
very large (diameter 50-53 mm.) individuals of plicatus, probably 
representative of populations from favorable moisture conditions. 
The vast majority of specimens are 38-43 mm. in diameter, with the 
extremes ranging from 36-45.5 mm. There have been no collections 
of individuals equaling the size of hydiana in the last 125 years. Size 
variation in five populations is summarized in Table XII. 

Some specimens (MCZ 64951 from Cerro Riecito, Acosta and 
MCZ 115523 from Tocuyo Valley) have the lips greatly thickened 
(fig. 34b) and the apertural structure begins to approach L. otis ortho- 
rhinus. The upper palatal lip region is much less obstructed by the 
teeth and the lower palatal tooth is not as wide and is more spade- 
shaped than in orthorhinus. Possibly these are from drier areas than 
the typical forms. 



124 



FIELDIANA: ZOOLOGY, VOLUME 50 



abed 




Fig. 36. Shells of: a, Labyrinthus plicatus, normal form, "Venezuela." Zurich; 
b-e, Labyrinthus marmatensis, Angelopolis, Antioquia, Colombia. Neuchatel. 
Holotype of angelopolites Piaget, 1912 (b, side; c, top; d, base; e, aperture);/, Laby- 
rinthus marmatensis, Marmato, Colombia, ANSP 8913. Aperture of holotype. 
Scale lines equal 10 mm. 

Both H. B. Baker and Wurtz (Joe. cit.) have dissected plicatus, 
which agrees closely in anatomy with L. otis orthorhinus. 



Labyrinthus marmatensis Pilsbry, 1910. Figure 36b-f. 

Helix (Labyrinthus) plicata var. Pilsbry, 1889, Man. Conch. (2), 5, p. 164, 

pi. 63, figs. 6-8 — Marmato, Colombia. 
Pleurodonte (Labyrinthus) plicata marmatensis Pilsbry, 1910, Proc. Acad. Nat. 

Sci., Philadelphia, 1910, p. 505 — Marmato, Colombia. 
Labyrinthus angelopolites Piaget, 1912, Mem. Soc. neuchateloise Sci. nat., 5, 

p. 258, pi. 10, figs. 1-6 — Angel6polis, near Titiribf, Antioquia, Colombia 

at 1,970 meters elevation (Fuhrmann!). 



SOLEM: NEOTROPICAL LAND SNAILS 125 

Range. — Cauca River Valley in Colombia from Marmato to An- 
gelopolis. 

Material— Colombia: CALDAS— Marmato (ANSP 8913, types 
of marmatensis, MCZ 154017). ANTIOQUIA— Jeric6( USNM 
424726) ; Angelopolis (Neuchatel, types of angelopolites) ; near Medel- 
lin (USNM 518435). No exact locality (Edinburgh, Zurich, CNHM 
132550). 

Diagnosis. — The prominent, sinuately curved parietal lamella 
runs diagonally into the lower parietal lip either at full height or after 
it starts descending; basal lip nearly straight with narrow, slanted 
crescentic lamella; lower palatal lip slightly concave with strong pos- 
terior indention, having a conical to spade-shaped, slightly recessed 
lamella; periphery acutely angulated with protruded keel; spire 
slightly elevated with flat or slightly rounded sides; color dark yellow 
brown. Diameter 26.6-37.2 mm. (mean 32.7 mm.), H/D ratio 0.318- 
0.428 (mean 0.363). 

Remarks. — Although originally described as a subspecies of L. pli- 
catus, the structure of the parietal lamella is totally different and the 
wide geographic separation also makes subspecific status unlikely. 
The original figures and descriptions of Labyrinthus angelopolites Pia- 
get, 1912 are highly inaccurate and misleading. Through the kind- 
ness of Dr. Lothar Forcart, Naturhistorisches Museum, Basel, it was 
possible to borrow the two cotypes. They are unquestionably the 
same as Pilsbry's species. The slightly larger (diameter 33.7 mm.) 
of the two cotypes is here selected as lectotype. 

Nearly all the specimens were 31-34 mm. in diameter, with only 
the shell found near Medellin being appreciably smaller (diameter 
26.6 mm.). All of the specimens measuring more than 34 mm. in 
diameter were without exact locality. 

Species of Uncertain Affinity 

The following two species were inadequately described and fig- 
ured. The few comparative remarks included are based on the de- 
scriptions and offered primarily in case new collections from the 
vicinity of the type localities should become available for study. 

Labyrinthus euclausus Beddome, 1908 

Labyrinthus euclausus Beddome, 1908, Proc. Malac. Soc. London, 8 (1), p. 20, 
text fig. — near Zaragoza, Colombia at 800 feet elevation in dense forests 
(Ernest Bell!). 



126 FIELD IANA: ZOOLOGY, VOLUME 50 

Remarks. — The single figure and description are totally inade- 
quate to enable recognition of this species. The mention of a large 
lower palatal tooth suggests that this is a member of the L. otis group, 
but the obvious failure of the parietal lamella to merge with the pari- 
etal lip and the only slightly sinuated basal lip prevent its association 
with any previously described species. 

Ernest Bell was a mining engineer, hence it is more likely that the 
type locality is in Antioquia rather than the towns of the same name 
in Cauca or Valle de Cauca. If this supposition is correct, then pos- 
sibly L. euclausus may be found to be a relative of L. marmatensis. 
The distinctive color pattern of reddish spiral bands on a yellow- 
white background is like L. unciger, but the tooth structure is obvi- 
ously different from both marmatensis and unciger. 

Labyrinthus sharmani (Gude, 1912). Figure 26c-d. 

Ambages sharmani Gude, 1912, Proc. Malac. Soc. London, 10 (1), pp. 21-22, 
2 figs. — Alejandrfa, 50 miles from Medellm, Colombia at 5,600 feet eleva- 
tion (Sharman!). 

Diagnosis. — The parietal lip is straight and markedly elevated 
from the wall while the parietal lamella is bifurcate — upper arm 
shorter and descending more gradually than the lower; basal lip mod- 
erately sinuated with a prominent knob-like lamella; lower palatal 
wall with single high, thick lamella; upper palatal wall with a plate- 
like lamella "nearly parallel with the peristome, its upper termination 
bent slightly forward"; umbilicus only slightly covered by basal and 
parietal lips; periphery rounded or obtusely angulated. Surface gran- 
ulose. Diameter 21.2 mm. 

Remarks. — The bifurcated parietal lamella, if not teratological, 
identifies this species immediately. In having a nearly straight pari- 
etal lip with simple relationship to the lamella, this species is much 
nearer to the L. isodon complex than to vexans or clappi. It may 
well be found to be a connecting link between the two complexes, but 
because of the apparent palatal teeth similarity to those found in 
bogotensis and otostomus, Gude's grouping may be correct. Only the 
type specimen in the British Museum (Natural History) (number 
1912.1.27.1) is known. 

The possibility exists that sharmani was based on abnormal indi- 
viduals of the isodon complex. 

GENUS Isomeria ALBERS, 1850 
Die Heliceen, p. 126. 

Type species. — Helix oreas Koch, 1844 by monotypy. 



SOLEM: NEOTROPICAL LAND SNAILS 127 

Range. — From Angelopolis and Frontino, Antioquia, Colombia 
south at medium elevations in the Andes to Chota District, Caja- 
marca, Peru, with two isolated species in the Sierra Nevada de Santa 
Marta, Magdalena, Colombia. A record from Ocafia in the southern 
part of the Sierra de Perija is questionable, but two species are known 
from Villavicencio, Meta, Colombia, and a third was described from 
Bogota. The largest number of species are from Ecuador, on both 
Amazonian and Pacific slopes. Only in the Pacific lowlands of Ecua- 
dor is a species (7. globosa) recorded from less than 1,500 feet elevation. 

Diagnosis. — Shell small to very large (diameter 18-73 mm.) ; glo- 
bose to helicoidal or depressed lenticular; surface sculpture of growth 
wrinkles, grooves, microscopic granulations, and /or heavy mallea- 
tions; periphery faintly to acutely angulated, occasionally with pro- 
truding keel, usually obtusely angulated; umbilicus normally closed 
or very narrowly open laterally, rarely distinctly open with an inter- 
nal groove visible, closure usually by extension of basal and parietal 
lips, sometimes by addition of an accessory plate; aperture strongly 
deflected in adult, lip thickened and reflected, usually with one or 
more small denticles, toothless in some species; parietal callus very 
thin to thickened with a narrow to wide raised edge, straight or 
evenly curved, sinuated only in /. inexpectata; basal and palatal lips 
thickened internally, evenly curved or straight; parietal wall gener- 
ally toothless, occasionally with very small conical tooth or short 
lamella; basal lip with 0-2 small denticles, sometimes joined by a 
callus; lower palatal lip toothless or with a small conical lamella, 
very rarely with a large tooth marked by posterior indentation (/. 
globosa) ; upper palatal lip with 0-2 small to medium-sized denticles. 
In the only species that has been dissected, /. globosa, the jaw, radula, 
pallial region and genitalia show exactly the same structures found 
in Labyrinthus, with the exception of having a penial appendage as 
well as an epiphallic flagellum. The vagina has a ring of low knobs 
around the base (fig. 4c) and both penis and vagina have the small 
hooked denticles topping the pilasters and ridges that so far have 
been found only in the mainland South American camaenids. 

Remarks. — Except for referring Labyrinthus vexans (Dohrn) and 
L. aenigmus (Dohrn) to Isomeria, the genus has been consistently 
recognized as a discrete unit, which is "confined to the high moun- 
tains of Ecuador and Colombia." The great reduction in size or total 
absence of the apertural teeth, which results in a widely open aper- 
ture, are in great contrast with the situation in Labyrinthus. Only in 
Isomeria inexpectata from the Sierra Nevada de Santa Marta and 



128 FIELDIANA: ZOOLOGY, VOLUME 50 

7. minuta from Sierra de Mariquita are there species that seem to be 
intermediate in shell characters. The only species of Isomeria that 
has been dissected, 7. globosa, cannot be considered typical, since it 
is not only the single lowland species (Pacific coast of Narino, Colom- 
bia and Ecuador) , but also the only species with a large lower palatal 
tooth marked by a posterior indention. 

The great deflection of the aperture allows recognition of the same 
three apertural zones seen in Labyrinthus, although Isomeria does not 
have a basal tooth separating the basal and palatal lips. There is no 
sharp separation of these areas, but the placement of teeth is such 
that no confusion of basal and lower palatal teeth seems possible. 

A basic shell difference between Labyrinthus and Isomeria lies in 
the parietal wall. In the former this is almost always an elevated lip 
that is often very grossly sinuated; in the latter this is a thin to thick- 
edged callus which is markedly sinuated only in a single species (7. in- 
expectata) . The callus in Isomeria may have a narrow, rounded thick- 
ened edge connecting the basal and palatal lips, but it is raised to 
form a distinct lip with reflected edge only in the 7. subelliptica group 
and I. oreas. Similarly, only in a very few species, 7. oreas, I. cyma- 
todes, I. subelliptica and some individuals of I. continua, is there a 
small crescentic to tubercular parietal lamella and only in I. inex- 
pectata is there a parietal tooth of moderate prominence. The vast 
majority of the species have no trace of parietal dentition. 

The basal lip can lack dentition, but have a heavy callus with the 
lip internally thickened (7. meyeri, I. meobambensis group) ; have a 
broad basal swelling or two basal teeth located one-third of the way 
from the umbilicus to the lower palatal lip (7. bituberculata group, 
7. aloagana, 7. triodonta) ; a single medial tooth (7. aequatoria, 7. gea- 
lei, I. morula) ; have the basal lip toothless; or have one of the above 
conditions so reduced by construction of a callus that the basal den- 
tition cannot be determined (most of the remaining species) . None 
of the species has large basal teeth. 

A clear majority of the species have a conical or crescentic lamel- 
late lower palatal tooth. All of the 7. oreas and 7. meobambensis 
groups (except the toothless 7. meyeri and 7. scalena) , 7. inexpectata, 
and three members of the 7. bituberculata group (7. hartwegi, I. me- 
demi, and 7. bourcieri) have this tooth. The remaining members of 
the 7. bituberculata complex and all of the 7. subelliptica group except 
7. minuta lack a lower palatal tooth. Only in 7. globosa is this tooth 
large and marked by a posterior indentation such as is found in most 
species of Labyrinthus. In the remaining species it is a small, incon- 



SOLEM: NEOTROPICAL LAND SNAILS 129 

spicuous denticle without any obvious functional significance. 7. 
meobambensis is unique in having a lateral extension running from 
the parietal tooth to the periphery. 

Upper palatal dentition is equally reduced. Small, rounded, in- 
conspicuous knobs are rarely seen in I. kolbergi and I. aequatoriana, 
commonly found in I. triodonta, I. juno and I. bituberculata, greatly 
reduced in I. inexpectata and I. hartwegi, and are very large in I. bour- 
cieri. In the latter species, the upper palatal tooth is distinctly 
larger than the lower palatal tooth. I. gealei and I. aequatoria are 
unique in having the peripheral groove accentuated with the lower 
part of the upper palatal lip forming a triangular tooth projecting 
into the aperture, much as in Labyrinthus otostomus. Apparently 
I. morula has much the same dentition as I. bituberculata. 

Few species have the periphery as acutely angulated as is com- 
mon in most Labyrinthus. Usually it is obtusely or only slightly an- 
gulated. Shell sculpture is quite variable, ranging from the nearly 
smooth surface of I. jacksoni to finely granulated (7. aequatoriana), 
heavily granulated (7. stoltzmanni) , with prominent radial grooves 
and growth lines (7. meobambensis) or with heavy malleations, par- 
ticularly on the body whorl (7. cymatodes). Each species seems to 
have its own particular combination of sculpture types, but these 
patterns are easily altered by erosion of the shell surface. Thus only 
slight use has been made of shell sculpture in preparing the keys, al- 
though in some cases it was the most obvious differentiating character. 

Much more than in Labyrinthus, there is a tendency toward clo- 
sure of the umbilicus. Only in 7. oreas, I. kolbergi, I. stoltzmanni, the 
7. subelliptica group, and 7. inexpectata can the umbilicus be said to 
be open. In a number of other species the umbilicus shows an open 
lateral crack, but in three of these— 7. cymatodes, I. fordiana and 7. 
scalena — there is an accessory plate of calcium that almost completes 
umbilical closure. Most of the species in the 7. bituberculata group, all 
of the I. meobambensis group and I. aequatoriana have the umbilicus 
completely closed by expansion of the parietal and basal lips. 

One of the more striking shell variations concerns the tendency 
toward lateral compression of the last one-quarter to one-third of the 
body whorl. This produces a very distinct alteration in shell outline 
from an evenly coiled, circular form to an asymmetrical, ellipsoidal 
pattern seen in, among others, 7. oreas, I. scalena, I. basidens gudeana 
and 7. stoltzmanni. This is not confined to a particular group of spe- 
cies, but appears, to a greater or lesser extent, within each group. 
The functional significance of the lateral compression is unknown. 



130 FIELDIANA: ZOOLOGY, VOLUME 50 

While a rather limited size range may be characteristic of any 
particular species, the presence of obviously dwarfed populations and 
occasional very large examples in almost every species for which more 
than a few examples were available, means that size is often of little 
use or a very misleading aid toward identification. For this reason, 
and since the positive shell characters separating species are fewer 
than in Labyrinthus, the mean size of all adult specimens together 
with the range in size has been given for each species. These figures 
are only general indications of size, since the material available was 
often strongly biased by the presence of a large sample of a dwarfed 
population (I. aequatoriana) or by scattered material from both large 
and small populations (I. oreas). 

Classification of Isomeria 

The great reduction in apertural dentition eliminates the most 
useful set of shell characters for grouping species. Delineation of 
species groups in Isomeria has been based on apparently clumped 
tendencies in respect to size, shape, sculpture and umbilical closure. 
Intragroup variability is sufficiently large that concise diagnoses of 
the species groups are impossible. 

Although its shape and size are very close to those of the I. bituber- 
culata complex, its striking tooth development and isolated geographic 
range are such that I. inexpectata is clearly separable. The bitubercu- 
lata group shows a depressed-globose form, closed or slightly angled 
periphery and relatively small size. 7. hartwegi is greatly modified 
in form and apertural dentition, but seems nearest to this group. A 
moderate contrast is seen in the I. subeUiptica group with the umbili- 
cus widely open for Isomeria and the very reduced dentition. Most 
of the species are larger in size than either of the first two groups. 

The I. meobambensis group has the umbilicus completely closed 
by expansion of the parietal callus and basal lip and the species are 
of medium size. That the I. oreas complex is a natural group seems 
dubious. Although most species have a narrowly to widely open 
umbilicus and show minor variations in shell features that seem clinal 
from species to species, three species (I. cymatodes, I. fordiana and 
I. scalena) show a peculiar form of umbilical closure, I. aequatoriana 
has the umbilicus closed as in the I. meobambensis group, and I. glo- 
bosa has very strongly developed lower palatal dentition. 

The species groups are more combinations for convenience in 
identification and study than any reasoned attempt at classification. 
There is simply too little evidence available to allow construction of 



SOLEM: NEOTROPICAL LAND SNAILS 131 

a phylogeny. As in Labyrinthus, the working assumption has been 
made that a grouping proceeding from the smaller to the larger may 
reflect some natural affinities. It is reasonable to hope that study of 
the soft parts will provide data toward a phylogenetic classification 
and particularly toward clearing up the currently insoluble problem 
of the single versus multiphyletic affinities of Isomeria and Laby- 
rinthus. 

Three specific names, I. calomorpha, I. fauna and /. equestrata, 
could not be identified from the original figures and descriptions. 
Only one of them was represented in collections and the specimens 
could be /. kolbergi (see p. 174). They are probably synonyms of 
other species, but cannot be identified at this time and are listed as 
nomina dubia (pp. 193-195). 

There is sufficient variability in the number and position of the 
teeth, degree of umbilical closure, peripheral angulation and size that 
construction of a key to the species groups is exceedingly difficult. 
Typical examples of any species can be easily placed, but the range 
of variation makes the keying of odd individuals hazardous. The 
following key has attempted to allow for the known range of varia- 
tion, but subsequent collections probably will make it inoperable. 

REVIEW OF THE SPECIES 

KEY TO THE SPECIES GROUPS OF ISOMERIA 

1. Parietal tooth absent or very small and not merging with sinuated edge of pari- 

etal callus 2 

Parietal tooth large, merging with edge of sinuated parietal callus. 

Group of Isomeria inexpectata new species 

2. Umbilicus closed to moderately open, but if opening more than just a narrow 

crack, having a lower palatal tooth and diameter more than 20 mm 3 

Umbilicus broadly open, only slightly narrowed by extension of basal and pari- 
etal lips; lower palatal tooth absent, or if present, diameter less than 20 mm. 

Group of Isomeria subelliptica 

3. Umbilicus completely closed by extension of basal and parietal lips, diameter 

less than 42 mm.; OR with a slight lateral umbilical crack, periphery very 
obtusely angulated, diameter less than 35 mm. and lower palatal tooth 

absent 4 

Umbilicus at least slightly open, OR with closure affected by construction of 
a secondary plate, OR if completely closed by extension of lips, then shell 
more than 43 mm. in diameter Group of Isomeria oreas 

4. Diameter 30-42 mm., specimens with no apertural teeth or swellings, OR a 

single lower palatal tooth with an upward lateral extension (fig. 47b), OR 
both a lower palatal tooth and a smaller upper palatal tooth located near a 

right or acutely angled periphery Group of Isomeria meobambensis 

Diameter under 30 mm.; OR having basal swellings or teeth, but no lower pal- 
atal tooth; OR with very obtusely angulated periphery and upper palatal 
tooth distinctly larger than lower palatal tooth. 

Group of Isomeria bituberculata 



132 FIELDIANA: ZOOLOGY, VOLUME 50 

Group of Isomeria inexpectata 

The single species from the isolated Sierra Nevada de Santa 
Marta shows affinities to both Isomeria and Labyrinthus. It tenta- 
tively has been placed in Isomeria, but differs from all other species 
groups in having a relatively large parietal lamella that runs into the 
raised edge of a sinuated parietal callus. 

Isomeria inexpectata, new species. Figure 37a-d. 

Diagnosis. — A small (diameter 23.3-24.6 mm.) species of Iso- 
meria immediately separable in having a distinctly lamellar parietal 
tooth that fuses with the lower part of the raised parietal callus. 
Form, color and general appearance are much as in I. basidens and 
I. bituberculata. The latter two differ in having the two basal teeth 
very close together, while in I. inexpectata they are widely separated. 
The moderately prominent lower palatal knob and faint trace of an 
upper palatal tooth also separate I. inexpectata from Isomeria medemi. 

Holotype. — United States National Museum number 599522. 
Siminchucua River, between San Sebastian de Rabago and Maman- 
canaca, 8,500-9,000 feet elevation, headwaters of Rio Fundacion, 
south slope of Sierra Nevada de Santa Marta, Magdalena, Colombia. 
Collected by M. A. Carriker from February 1-10, 1946. 

Description. — Shell small, depressed globose, with 43^ normally 
coiled whorls. Spire moderately elevated, flatly rounded above, 
H/D ratio 0.569. Apex and early spire worn, without trace of dis- 
tinctive sculpture. Lower whorls with weak radial growth lines, but 
no malleations or granulations. Periphery faintly angulated with a 
lighter color zone. Color reddish brown with numerous greenish- 
yellow flecks, especially numerous above periphery. Lip white, with- 
out any brownish tint. Umbilicus very narrowly open, partly closed 
by extension of basal and parietal lips, contained 17.6 times in the 
diameter. Aperture ovate, only slightly deflected, inclined about 40° 
from the shell axis. Parietal wall with single crescentic lamella run- 
ning into lower parietal callus. No raised parietal lip, but a heavy 
sinuated lower parietal callus extending from fusion with parietal 
lamella to umbilicus; upper parietal wall with faint trace of a broad 
callus, much reduced from lower parietal callus. Basal lip thickened, 
narrowly reflected, with two inconspicuous, rather widely separated 
knobs. Lower palatal lip with a prominent, triangular, raised knob. 
Upper palatal lip with a faint trace of a tooth located just on the 
periphery. Height of holotype 14.0 mm., diameter 24.6 mm. 






SOLEM: NEOTROPICAL LAND SNAILS 



133 




Fig. 37. Isomeria inexpectata: Siminchucua River, Sierra Nevada de Santa 
Marta, Colombia, USNM 599522. Holotype (a-c), paratype (d). (a, base; b, top; 
c, side; d, aperture). Scale lines equal 10 mm. 

Range. — Known only from the type locality. 

Paratypes.— USNM 599522, CNHM 132554. 

Remarks. — While the general appearance of the shell is unques- 
tionably that of the bituberculata group of Isomeria, even casual in- 
spection of the teeth shows important differences. No other species 
of Isomeria has such a distinct parietal lamella. A few have a small, 
circular or elongated, raised callus on the parietal wall, but none has 
a lamella. Furthermore, the raised parietal callus edge in Isomeria 
is straight or slightly curved. In /. inexpectata the parietal callus has 
the same sinuated shape seen in the more complexly toothed mem- 
bers of the Labyrinthus isodon complex. As in that group, the pari- 
etal lamella of /. inexpectata fuses directly with the lower portion of 
the parietal callus, with the upper portion being greatly reduced in 



134 FIELDIANA: ZOOLOGY, VOLUME 50 

size. Furthermore, in the I. bituberculata complex, the two basal lip 
teeth are usually very close together or actually fused and elevated 
on a slight ridge (see fig. 40). Only in I. medemi are they widely 
separated. In I. inexpectata, the basal lip has two widely separated, 
low swellings with the outer located in the normal position of the 
basal tooth in Labyrinthus. The lower palatal wall of I. inexpectata 
has a prominent raised knob and there is a faint trace of a swelling 
on the periphery. 

The structure of the apertural teeth is precisely what would be 
expected if Labyrinthus vexans or L. isodon had the tooth size greatly 
reduced, and is rather similar to the Caracas form of L. leucodon. 
It is quite different in size and tooth position from I. medemi and 
its relatives, although the shell shape and color are precisely as in 
I. bituberculata. Furthermore, the Sierra Nevada de Santa Marta is 
far removed from the primary distribution of Isomeria. Isomeria 
oreas has been found at Angel6polis, Antioquia and J. continua from 
the area around Bogota, but neither of these is at all similar in ap- 
pearance. I. bituberculata and its allies are primarily found in Ecua- 
dor, with I. neogranadensis from the Caldas-Tolima border region, 
J. basidens described from "Bogota," and only J. medemi is known 
from the Sierra Nevada de Santa Marta. 

Available data is obviously inadequate to tell whether I. inex- 
pectata represents a local Jsorama-like derivative of Labyrinthus in 
the Sierra Nevada de Santa Marta, or whether it has phyletic rela- 
tionships with other Isomeria from southern Colombia and Ecuador. 
Because of its altitudinal range, 8,500-9,000 feet, general appearance 
as an Isomeria, presence of I. medemi in the same range, and dissimi- 
larity in tooth structure to the Labyrinthus of the Sierra Nevada de 
Santa Marta (L. clappi and L. sieversi), I have arbitrarily placed I. 
inexpectata in Isomeria. 

Only three specimens are known of this very intriguing species. 
Size and shape variation is summarized in Table XIII. One para- 
type contained remnants of the soft parts. Softening in trisodium- 
phosphate revealed that only the foot, mantle collar and an encysted 
nematode had escaped the attention of dermestid beetle larvae. These 
structures, at our present level of knowledge, yield no data on generic 
classification. 

Group of Isomeria bituberculata 

These are small to medium sized species (diameter 20-36 mm.) 
with either a prominent basal lip swelling or two basal teeth, the pe- 






SOLEM: NEOTROPICAL LAND SNAILS 135 

riphery usually obtusely angulated, the umbilicus completely closed 
or at most narrowly open laterally, no parietal tooth present, and 
often with the last part of the body whorl moderately constricted. 

The species are sufficiently similar to justify grouping, although 
J. hartwegi could be considered a dwarf member of the /. meobam- 
bensis group. Possibly two weakly differentiated series of species 
could be recognized. The Colombian /. basidens and /. neograna- 
densis have a broad low basal lip swelling and no other teeth, while 
the Ecuadorean shells and the single species from the Sierra Nevada 
de Santa Marta have a pair of basal teeth and other denticles. /. basi- 
dens is smaller and with a more obtusely angled periphery than J. neo- 
granadensis. I. medemi has two rather widely set basal teeth and a 
small lower palatal tooth, but no trace of an upper palatal tooth. 
/. hartwegi has a nearly right angled periphery, small lower palatal 
tooth, and an evenly elevated spire. It is a much thinner shell than 
the large, heavy, obtusely angulated /. juno, which lacks the lower 
palatal tooth. Probably J. juno is most closely related to /. bituber- 
culata, which differs in its more globose shell, less angulated periphery 
and thinner shell and lips. Finally, /. bourcieri has a color pattern 
duplicated only by Labyrinthus magdalenensis, a lower palatal tooth, 
and an upper palatal tooth that is larger than the lower one. 

Data on two of the three Colombian species is much too fragmen- 
tary to allow delineation of their geographic ranges. The third, I. 
medemi, is known from two examples. Of the Ecuadorean species, 
/. bourcieri, I. bituberculata and I. juno have been reported from the 
same areas (Upper Rio Esmeraldas, Napo and Pastaza drainages), 
but with no data as to ecology. There are no cited elevations for 
/. juno and only two (8,200 feet) for /. bourcieri. The several cited 
elevations for I. bituberculata lie between 3,900-13,000 feet. Locali- 
ties without elevation data range much lower, reaching 1,680 feet at 
Napo. These are regional citations, of course, and give no indication 
of true altitudinal range. /. hartwegi has a much more southern range, 
having been reported from 3,000 feet elevation in the Catamayo 
Valley north to Cuenca (8,400 feet) and then in lowland areas of the 
Pacific drainage near Guayaquil (Cerritos de Taura and La Galia, 
Yaguachi). 

KEY TO THE ISOMERIA BITUBERCULATA GROUP 

1. Basal lip with a small to prominent swelling 2 

Basal lip with one or more teeth, occasionally partly obscured by a callus .... 5 

2. Shell surface without malleations 4 

At least part of shell surface with malleations 3 



136 FIELDIANA: ZOOLOGY, VOLUME 50 

3. Malleations on lower part of body whorl; Sierra Nevada de Santa Marta. 

/. medemi new species 
Upper part of spire malleated; Cauca /. basidens gudeana (Ancey, 1904) 

4. Basal swelling very small; diameter 34 mm. . . . /. neogranadensis (Pfeiffer, 1845) 
Basal swelling moderately prominent; diameter 24 mm. 

/. basidens basidens (Mousson, 1873) 

5. A lower palatal tooth present 6 

No lower palatal tooth present 7 

6. Periphery right angled; upper palatal tooth weak or absent; color brown. 

/. hartwegi (Pfeiffer, 1846) 
Periphery obtusely angulated to rounded; color reddish brown with yellow 
markings; upper palatal tooth larger than lower palatal tooth. 

J. bourcieri (Pfeiffer, 1853) 

7. Teeth reduced in size; periphery right angled with lighter color band; lip and 

callus very thick /. juno (Pfeiffer, 1850) 

Teeth larger and lip thinner; periphery obtusely angulated to rounded without 
a lighter color band /. bituberculata (Pfeiffer, 1853) 

Isomeria medemi, new species. Figure 38a-d. 

Diagnosis. — A rather small (diameter 25.7-28.2 mm.) species of 
Isomeria with two prominent basal teeth, a small lamellar lower pal- 
atal tooth, closed umbilicus and obtusely angulated periphery. I. in- 
expectata differs in having a parietal lamella and open umbilicus. The 
nearest relatives seem to be in the /. bituberculata complex, but all 
of these have less prominent basal teeth, lack the lower palatal tooth 
or have a more depressed form. 

Holotype. — Chicago Natural History Museum number 133261. 
Finca La Granja, San Lorenzo Ridge, Sierra Nevada de Santa Marta, 
Magdalena, Colombia at 8,200-8,850 feet elevation. Collected by 
Carlos Alberto Velasquez and Fred Medem from February 19-25, 
1964. 

Description. — Shell rather small, somewhat depressed globose, 
with slightly less than 43^ normally coiled whorls. Spire elevated, 
slightly flattened on apex, nearly flat laterally, H/D ratio 0.604. 
Shell very worn, with only faint traces of radial ribbing remaining. 
Last part of body whorl showing marked malleations. Periphery 
obtusely angulated, becoming rounded on last one-third of body 
whorl. Periostracum and color completely worn off shell. Umbili- 
cus completely closed by expansion of basal and parietal lips. Aper- 
ture ovate, moderately deflected, inclined about 45° from the shell 
axis. Parietal wall with prominent callus, edge slightly sinuated. 
Basal lip with two rather widely spaced, prominent teeth, outer one 
slightly larger. Lower palatal lip with small, crescentic lamellar 
tooth, relatively narrow and not extending posteriorly. Upper pal- 



SOLEM: NEOTROPICAL LAND SNAILS 



137 




Fig. 38. Isomeria medemi: Finca La Granja, San Lorenzo, Sierra Nevada de 
Santa Marta, Colombia, CNHM 133261. Holotype (a, top; b, base; c, side; 
d, aperture). 



atal lip without dentition, only slightly reflected at upper margin, 
becoming more sharply reflected with posterior gutter near periph- 
ery. Lower palatal lip strongly reflected. Basal lip recurved, ap- 
pressed to basal margin. Height of holotype 17.0 mm., diameter 
28.2 mm. 

Paratype. — CNHM 145160 from the type locality. 

Remarks. — Description of this species from two dead, partly bro- 
ken shells is warranted only because of the light it sheds on the re- 
lationships of /. inexpectata. By confirming the development of 
"typical" Isomeria in the Sierra Nevada de Santa Marta, /. medemi 
gives a firmer basis for placing /. inexpectata in this genus rather than 
in Labyrinthus. 

The type locality of /. medemi is located on the same northwest 
spur of the mountain mass as is L. clappi. The latter is known only 



138 FIELDIANA: ZOOLOGY, VOLUME 50 

from 4,000-5,000 feet elevation, while the types of /. medemi were 
taken at 8,200-8,850 feet elevation. /. inexpectata is known from 
8,500-9,000 feet elevation on the southwest face of the main Sierra, 
at least 50 air miles from the San Lorenzo spur. The other camaenid 
described from the Sierra Nevada de Santa Marta, L. sieversi, has 
been found in the center of the north face at 5,500 feet (San Miguel), 
the northeast spur of the mass at 2,500 feet (Los Gorros) and at 330- 
670 feet (Oblo), whose exact locale is not known to me. 

The relationships of /. medemi are unquestionably with the bi- 
tuberculata complex. It is easily distinguished by its isolated geo- 
graphic range, larger basal teeth, single lower palatal tooth and 
elevated shape. The other two Colombian species, I. basidens and 
/. neogr canadensis, lack a lower palatal tooth, while all the Ecuadorean 
species obviously have different tooth size and numbers. 

This species is named after one of its collectors, Dr. Fred Medem, 
who has contributed so much to knowledge of the Colombian fauna. 

Isomeria basidens basidens (Mousson, 1873). Figures 39a-c, 40a. 

Helix basidens Mousson, 1873, Malak. Blatt., 21, pp. 2-3 — Bogota (Wallis!); 

Pfeiffer, 1876, Novit. Conch., 4, pp. 118-119, pi. 127, figs. 7-9; Pfeiffer, 

1876, Monog. helic. viv., 7, p. 362. 
Helix (Isomeria) basidens Mousson, Pilsbry, 1889, Man. Conch. (2), 5, p. 154, 

pi. 48, figs. 52-54. 
Pleurodonte (Isomeria) basidens (Mousson), Pilsbry, 1894, Man. Conch. (2), 

9, p. 94. 

Range. — Known only from the type collection. 

Material— Colombia: CUNDINAMARCA— Bogota (Zurich, 
holotype of basidens Mousson). 

Diagnosis. — Basal lip with a moderately prominent swelling; um- 
bilicus closed; lip slightly brown tinted; parietal callus very thin, edge 
not elevated; surface with very fine granulations and growth striae, 
but no malleations; periphery very obtusely angulated. Diameter 
25.4 mm. 

Remarks. — The smaller size, less sharply keeled periphery, more 
prominent basal lip swelling and weaker surface sculpture easily sep- 
arate basidens from neogranadensis. Subspecies gudeana has the basal 
lip swelling much more prominent and is malleated on the upper spire 
(see fig. 39d). The type locality "Bogota" could mean anywhere 
within a 100-mile radius of the city. No more recent material has 
been collected. The type specimen measures 14.2 mm. high, diam- 
eter 25.4 mm., H/D ratio 0.559, with 43/g whorls. 



SOLEM: NEOTROPICAL LAND SNAILS 139 

The slightly larger /. medemi differs in having two rather widely 
separated basal teeth and a lower palatal tooth. 

Isomeria basidens gudeana (Ancey, 1904). Figures 39d-e, 40b. 

Helix (Isomeria) neogranadensis var., Dunker, 1882, Jahr. d. Malak. Gesell., 
9, pp. 377-378, pi. 11, figs. 5-6— locis uliginosus, Ecuador; Pilsbry, 1889, 
Man. Conch. (2), 9, p. 153, pi. 62, figs. 22-23; Kobelt, 1894, Syst. Conch. 
Cab., I (12), 4, p. 694, pi. 198, figs. 5-6. 

Pleurodonte gudeana Ancey, 1904, Jour, de Conchy., 52, p. 297 — based on fig- 
ures in Kobelt (loc. tit.). 

Pleurodonte (Isomeria) gudeana (Ancey), Pilsbry, 1926, Proc. Acad. Nat. Sci., 
Philadelphia, 78, pp. 4-5, pi. 2, figs. 1-3 — either La Cumbre, Cordillera 
Occidental, Prov. El Valle or mountains east or west of Popayan, Prov. 
Cauca, Colombia. 

Pleurodonta (sic) basidens rugospira n. subsp., Pilsbry, 1926, op. tit., 78, p. 15 — 
in explanation of Plate 2 for figs. 1-3, referred to in text as P. gudeana 
Ancey, 1904. 

Range. — Probably Central Cauca, Colombia. 

Material— Colombia: CAUCA— Popayan (ANSP 132449, CNHM 
78831) ; Volcan de Purace\ Paletara (R. Wright Barker, CNHM 
132553). "Ecuador" (SMF 26347). 

Diagnosis. — Basal lip with a prominent swelling; umbilicus closed; 
outer lip slightly tinted; parietal callus nearly absent; upper part of 
spire with heavy malleations, lower part with weak malleations and 
very fine granulations; periphery very obtusely angulated. Diam- 
eter 25.6-29.6 mm., H/D ratio 0.599-0.625. 

Remarks. — The more prominent basal lip swelling, slightly dis- 
torted form of coiling and the presence of marked malleations on the 
upper spire at once separate gudeana from basidens. They are con- 
sidered subspecies in view of their general similarity, but could be 
found to be specifically separable. Both sets of gudeana have the 
malleations clearly visible for the first 2^-23^ whorls, gradually be- 
ing replaced by the very fine granulations found on the lower spire 
and shell base. J. medemi differs in having the malleations appear 
near the periphery on the last half of the body whorl. Size variation 
of /. 6. gudeana in the three adults with exact locality data is minor, 
height 15.5-16.1 mm., diameter 25.6-26.9 mm., H/D ratio 0.599- 
0.615, with 4-4J4 whorls. 

The Paletara Valley is between 8,850-11,200 feet elevation, while 
La Cumbre and Popayan are between 5,150-5,775 feet elevation. 
Neither set of specimens has data as to the elevation from which the 
specimens were taken, so that the altitudinal range is unknown. All 
of the possible localities are in the upper Cauca drainage. 



140 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 39. Isomeria basidens: a-c, Isomeria basidens basidens, Bogota, Colombia. 
Zurich. Holotype (a, top; b, base; c, side); d-e, I. b. gudeana, La Cumbre, Colom- 
bia, CNHM 78831 (d, top; e, side). Scale line equals 10 mm. 



Isomeria neogranadensis (Pfeiffer, 1845). Figures 40c, 41a-c. 

Helix neogranatensis (sic), Pfeiffer, 1845, Proc. Zool. Soc. London, 1845, p. 64 
— Quendeu Mt., Colombia. 

Helix neogranadensis Pfeiffer, 1848, Monog. helic. viv., 1, p. 296; Reeve, 1852, 
Conch. Icon., Helix, pi. 99, fig. 548; Pfeiffer, 1853, Monog. helic. viv., 3, 
p. 206; Pfeiffer, 1854, Syst. Conch. Cab., I (12), 3, pp. 435-436, pi. 151, 
figs. 13-14 (plate issued in 1853); Pfeiffer, 1876, Monog. helic. viv., 7, 
p. 358. 



SOLEM: NEOTROPICAL LAND SNAILS 



141 




Fig. 40. Apertures of: a, Isomeria basidens basidens, Bogota, Colombia. 
Zurich. Holotype; b, Isomeria b. gudeana, La Cumbre, Colombia, CNHM 78831; 

c, Isomeria neogranadensis, "New Granada." Zurich. Probably a paratype; 

d, Isomeria bituberculata, Banos, Tungurahua, Ecuador, CNHM 117842. Scale 
line equals 10 mm. 



Helix (Isomeria) neogranadensis Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, 

p. 153, pi. 48, figs. 40-42. 
Pleurodonle (Isomeria) neogranadensis (Pfeiffer), Pilsbry, 1894, Man. Conch. 

(2), 9, p. 94. 

Range. — Known only from the type locality. 



142 FIELDIANA: ZOOLOGY, VOLUME 50 

Material. — "New Granada" (Zurich, ex Mousson, Marg(?raf), 
1845, probably a paratype. 

Diagnosis. — Basal lip with a very faint swelling; umbilicus closed; 
lip flesh tinted; surface without malleations, but with fine granula- 
tions; periphery slightly to obtusely angulated; parietal callus very 
thin with a faint raised edge. Diameter 34 mm. 

Remarks. — The larger size, more angulated periphery, and reduced 
basal lip swelling are the main characters separating basidens and 
neogranadensis. The single specimen examined is more sharply keeled 
than the specimen figured by Pfeiffer (loc. cit.) and much more sharply 
carinated than the specimen figured by Reeve (loc. cit.). It is 33.7 
mm. in diameter, 17.1 mm. in height, H/D ratio 0.507, with 4J/£ 
whorls. 

The type locality "Quendeu Mt." probably refers to the area of 
the Central Andes between Parama de Barragan and Nevado del 
Quindio in the Caldas-Tolima border area. 

Isomeria bituberculata (Pfeiffer, 1853). Figures 40d, 41d. 

Helix bourcieri Reeve, 1852 (not Pfeiffer, 1853), Conch. Icon., Helix, pi. 99, 
fig. 545 — Otoralo (=Otavalo) (error), Ecuador (Bourcier!) (issued in May, 
1852); error in labeling. 

Helix bituberculata Pfeiffer, 1853, Monog. helic. viv., 3, p. 242; Pfeiffer, 1854, 
Proc. Zool. Soc. London, 1852, p. 153 — near Tunguragua, Ecuador (Bour- 
cier!) (issued June 27, 1954); Pfeiffer, 1854, Syst. Conch. Cab., I (12), 3, 
p. 369, pi. 139, figs. 14-15 (plate issued in 1852); Pfeiffer, 1859, Monog. 
helic. viv., 4, p. 292; Pfeiffer, 1868, Monog. helic. viv., 5, p. 383; Hidalgo, 
1870, Moluscos del Viaje al Pacifico, pp. 14-15 — Quito, Ecuador (Paz and 
Martinez!); Pfeiffer, 1876, Monog. helic. viv., 7, p. 442; Dohrn, 1879, 
Jahrb. d. Malak. Gesell., 6, p. 186; Hidalgo, 1893, Obras Malac, 3, pp. 
80, 176. 

Helix (Isomeria) bituberculata (Pfeiffer), von Martens, 1860, Die Heliceen, 
2nd ed., p. 156; Pilsbry, 1889, Man. Conch. (2), 5, pp. 154-156, pi. 47, 
figs. 36-38; Reibisch, 1896, Abhl. naturwiss. Gesell. Isis, Dresden, 7, p. 55 
— San Rafael, Tunguragua, Ecuador at 9,000 feet elevation (Wolf!); Ger- 
main, 1907, Bull. Mus. National hist, nat., Paris, 13, p. 54 — Mindo, 
Ecuador (Rivet!). 

Dentellaria bituberculata (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 165 — 
Nanegal (Wolf!). 

Dentellaria tridentula Miller, 1878, Malak. Blatt., 25, p. 165, pi. 7, figs. 5a-c — 
Nanegal (Wolf!), Val de Pilat6n (Boetzkes!), Ecuador. 

Dentellaria latidentata Miller, 1878, Malak. Blatt., 25, p. 166, pi. 8, figs, la-c— 
Nanegal, Ecuador (Wolf!). 

Isomeria bituberculata (Pfeiffer), Cousin, 1887, Bull. Soc. Zool. France, 12, 
p. 256 — San Antonio, trail from Quito to Gualea, Ecuador (Cousin!). 



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144 FIELDIANA: ZOOLOGY, VOLUME 50 

Isomeria latidentata (Miller), Cousin, 1887, loc. cit., 12, p. 257 — San Antonio, 

Travenia, Ecuador (Cousin!). 
Isomeria trident ula (Miller), Cousin, 1887, loc. cit., 12, p. 257 — Alaspungo, trail 

from Quito to Gualea and trail from Aloag to Chones, Ecuador (Cousin!). 
Helix (Isomeria) bituberculata var. tridentula (Miller), Pilsbry, 1889, Man. 

Conch. (2), 5, pp. 155-156, pi. 43, figs. 43-45. 
Helix (Isomeria) bituberculata var. latidentata (Miller), Pilsbry, 1889, Man. 

Conch. (2), 5, p. 156, pi. 43, figs. 50-52. 
Pleurodonte (Isomeria) bituberculata (Pfeiffer, not Reeve), Pilsbry, 1894, Man. 

Conch. (2), 9, p. 94. 
Helix (Isomeria) bourcieri (Reeve), Germain, 1910, Miss. Arc de Meridien 

equatorial, 9 (3), pp. C.19-C.20— Mindo, Ecuador (Rivet!). 

Range. — Central Ecuador; rather widely distributed in the Upper 
Rio Esmeraldas drainage on the Pacific slope and the Rio Napo and 
Rio Pastaza on the Amazonian slopes. The few reported elevations 
are between 3,900-13,100 feet. 

Material.— Ecuador: Chimborazo (CNHM 78832, ANSP 106859) ; 
"Quito" (CNHM 95505, CNHM 102457, ANSP 1460, ANSP 33138, 
Zurich, ZMA, SMF, Edinburgh); Mera, Oriente Prov. (CNHM 
86666, Jackson 9549, Jackson 9668, CNHM 117845, CNHM 117846, 
ANSP 227903, Jackson 5727); Napo (CNHM 117844, Jackson 6138, 
Jackson 9550) ; Banos, Tungurahua Prov. (CNHM 117842, CNHM 
117843, Jackson 6251); Nanegal (ANSP); Rio Nanegal at 1,200 me- 
ters (SMF 156319); Mindo (ANSP 189040); Puyo (Jackson 9339); 
Ibarra (Jackson 9736) ; San Fernando (Jackson 7507) ; Topo (Jackson 
9989); Mt. Tungurahua, 4,000 meters (MCZ 113918); Guama Hill, 
Banos, 2,000 meters (MCZ 139814, MCZ 65724); Chaupi, Mt. Tun- 
gurahua (MCZ 195502). 

Diagnosis. — Basal lip with two teeth set close together, occasion- 
ally obsolete, usually small, sometimes prominent; upper palatal lip 
often with a very small conical tooth; umbilicus rarely closed, but 
usually narrowly open; periphery rounded to very obtusely angu- 
lated ; lip with brownish tinge above periphery. Diameter 20-33 mm. 
(mean 26.3 mm.), H/D ratio 0.546-0.715 (mean 0.618). 

Remarks. — This species is highly variable in dentition, size and 
umbilical opening, but available material is insufficient to evaluate 
the importance of these features. 

Two variants have been named. Both were collected by Wolf 
near Nanegal, but it is not known if they are ecotypes or extreme 
variants in one population. Form tridentula (diameter 28 mm.) has 
a closed umbilicus and a small upper palatal tooth; form latidentata 
(diameter 32 mm.) has the basal teeth prominent and connected by 



SOLEM: NEOTROPICAL LAND SNAILS 145 

a ridge, a large upper palatal tooth, and a moderately open umbilicus; 
typical bituberculata (diameter 22 mm.) has two small basal teeth and 
a nearly closed umbilicus. Most specimens are not referable to one 
of the three named variations, but are intermediate in nature. 

Size varied from 20-33 mm., covering the range of the types of all 
three named forms. No large sets of localized material were avail- 
able, but even in the small sets (see Table XIII) great size and shape 
variation can be observed. Museum shells show a clearly bimodal 
distribution of diameters (see below), but no such variation in obesity 
index. Quite possibly bituberculata will eventually be split into local 
races or ecologic forms, but present data is inadequate for subspe- 
cific treatment. 

Diameter in mm. 
20.7 22.2 23.7 25.2 26.7 28.2 29.7 31.2 32.7 
No. of specimens 1 20 18 13 4 6 14 12 5 

H/D ratio 
0.538 0.563 0.588 0.613 0.638 0.663 0.678 0.713 
No. of specimens 1 11 16 22 24 16 2 1 

The problem of Reeve's switch of the figures and descriptions of 
bourcieri and bituberculata is discussed under /. bourcieri. For the 
sake of nomenclatural stability, I have utilized Pfeiffer's concept of 
the species and consider that the figures in the Conchylien Cabinet 
represent the type form of bituberculata. 

The rather similar I. basidens basidens differs in being more de- 
pressed with only a basal swelling and a less indented umbilical area. 

The few elevation records, 3,900-13,100 feet, probably cover only 
the upper part of the altitudinal range. 

Isomeria juno (Pfeiffer, 1850). Figures 41e, 42a. 

Helix juno Pfeiffer, 1850, Zeits. f. Malak., 7 (5), pp. 66-67— Andes of Colom- 
bia; Reeve, 1852, Conch. Icon., Helix, pi. 99, fig. 547; Pfeiffer, 1853, 
Monog. helic. viv., 3, pp. 208-209; Pfeiffer, 1853, Syst. Conch. Cab., I 
(12), 3, pp. 304-305, pi. 127, figs. 4-5 (plate issued in 1852); Pfeiffer, 1859, 
Monog. helic. viv., 4, p. 242; Pfeiffer, 1868, Monog. helic. viv., 5, p. 315; 
Hidalgo, 1870, Moluscos del Viaje al Pacifico, pp. 13-14, pi. 1, figs. 6-7 — 
Napo and Baeza, Ecuador (Martinez!); Pfeiffer, 1876, Monog. helic. viv., 
7, p. 361; Hidalgo, 1893, Obras Malac, 3, pp. 80, 175-176. 

Helix (Isomeria) juno Pfeiffer, von Martens, 1860, Die Heliceen, 2nd ed., 
p. 156; Pilsbry, 1889, Man. Conch. (2), 5, pp. 152-153, pi. 45, figs. 13-14; 
Germain, 1907, Bull. Mus. National hist, nat., Paris, 13, p. 54 — Mindo, 
Ecuador (Rivet!); Germain, 1910, Miss. Arc de Mendien Equatorial, 9, 
pp. C.15-C.16. 



146 



FIELDIANA: ZOOLOGY, VOLUME 50 








Fig. 41. Shells of: a-c, Isomeria neogranadensis, "New Granada." Zurich. 
Probably a paratype (a, top; b, base; c, side); d, Isomeria bituberculata, Banos, 
Tungurahua, Ecuador, CNHM 117842; e, Isomeria juno, Mera, Ecuador, CNHM 
86650; /, Isomeria hartwegi, La Galia, Yaguachi, Ecuador, CNHM 40647. Scale 
line equals 10 mm. 



Isomeria juno (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 171— Val de Pila- 
ton, Ecuador (Boetzkes!); Cousin, 1887, Bull. Soc. Zool. France, 12, pp. 
256-257 — Est. Pegado, Baeza, Napo, Ecuador (Cousin!). 

Pleurodonte (Isomeria) juno (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 9, p. 94. 

Range. — Ecuador: Recorded localities are — Napo, Nachiyacu and 
Baeza on the Rio Napo; Puyo and Mera on the Rio Pastaza; Mindo, 
Nanegal, Val de Pilaton on tributaries of the Rio Guallabamba. No 
specimens have altitudinal data with them. 



SOLEM: NEOTROPICAL LAND SNAILS 



147 



Material. — Ecuador (Edinburgh) : Mera (CNHM 88650, Jackson 
6998) ; Baeza (USNM 608877, SMF 82549) ; Nanegal (ANSP) ; Nachi- 
yacu (Jackson 5104, ANSP 170706); Puyo (Jackson 6997, ANSP 
170728); Oriente Prov. (CNHM 72338, CNHM 72349, USNM 
628798); "Quito" (CNHM 95575, CNHM 102397, Zurich). 

Diagnosis. — Basal lip with two inconspicuous swellings near the 
umbilicus, visible in subadults as distinct teeth; upper palatal lip 
usually with low swelling; umbilicus completely closed; umbilical 
callus and lip grossly thickened internally, obscuring teeth; periph- 
ery obtusely angulated with lighter color band; parietal callus with 
thick edge; surface with rather noticeable malleations and grooves. 
Diameter 28.1-35.8 mm. (mean 32.5 mm.), H/D ratio 0.513-0.657 
(mean 0.600). 

Remarks. — This can obviously be derived from /. bituberculata, 
differing in the more angulated periphery, with lighter color band, 



abc 




Fig. 42. Shells of: a, Isomeriajuno, Mera, Ecuador, CNHM 86650. Aperture; 
b, Isomeria hartwegi, La Galia, Yaguachi, Ecuador, CNHM 40647. Aperture; c-d, 
Isomeria bourcieri, Mindo, Ecuador, CNHM 117847 (c, aperture; d, side). Scale 
lines equal 10 mm. 



148 FIELDIANA: ZOOLOGY, VOLUME 50 

greatly thickened shell and lip, and the umbilical callus that reduces 
the prominence of the teeth. Most specimens show only the faintest 
trace of the upper palatal tooth and the basal teeth are reduced to 
low swellings. 

No data is available on the ecological relationship of juno and 
bituberculata. Both have been reported from the same locality, al- 
though they were not collected at the same time. Apparently I. juno 
lives on both the Amazonian and Pacific slopes of the Ecuadorean 
Andes. No data is available as to its altitudinal range. The larger 
size, much thicker and heavier shell and absence of a lower palatal 
tooth separate I. juno from J. hartwegi. In older collections, I. aequa- 
toria has been confused with I. juno. The former has a lower palatal 
tooth, lacks any surface malleations, and is generally larger in size. 

Size and shape variation is within rather narrow limits, the ranges 
in diameter and obesity index being much less than in I. bourcieri or 
I. bituberculata. 

Size variation in four localized sets is summarized in Table XIII. 
Plotting of the diameter and obesity index for all available specimens 
showed only slightly skewed distributions. 







Diameter in mm. 








28.5 


30.5 31.5 


32.5 33.5 34.5 


35.5 


No. of specimens 


1 


1 4 12 
H/D ratio 


13 19 2 


2 




0.515 


0.545 0.575 


0.605 0.635 


0.665 


No. of specimens 


1 


2 19 


17 11 


4 


meria bourcieri (Pfeiffer, 1853). Figure 42c-d. 





Helix bituberculata Reeve, 1852 (not Pfeiffer, 1853), Conch. Icon., Helix, pi. 99, 
fig. 544 — Tungaragua (=Tungurahua) (error), Ecuador (Bourcier!) (issued 
in May, 1852). 

Helix bourcieri Pfeiffer, 1853, Monog. helic. viv., 3, p. 209; Pfeiffer, 1854, Proc. 
Zool. Soc. London, 1852, p. 153 — Otoralo (=Otovalo), Ecuador (issued 
June 27, 1854); Pfeiffer, 1854, Syst. Conch. Cab., I (12), 3, pp. 368-369, 
pi. 139, figs. 12-13 (plate issued in 1852); Pfeiffer, 1859, Monog. helic. viv., 
4, p. 243; Pfeiffer, 1868, Monog. helic. viv., 5, p. 315; Hidalgo, 1870, 
Moluscos del Viaje al Pacifico, pp. 15-16 — Nanegal, Ecuador (Martinez!); 
Pfeiffer, 1876, Monog. helic. viv., 7, p. 362; Hidalgo, 1893, Obras Malac, 
3, pp. 80, 178. 

Helix (Isomeria) bourcieri Pfeiffer, von Martens, 1860, Die Heliceen, 2nd ed., 
p. 156; von Martens, 1885, Conch. Mitteil., 2 (5-6), p. 157— Nanegal, 
Ecuador (Stubel!); Pilsbry, 1889, Man. Conch. (2), 5, p. 156, pi. 48, figs. 
49-51; Reibisch, 1896, Abhl. Naturwiss. Gesell. Isis, Dresden, 7, p. 55 — 



SOLEM: NEOTROPICAL LAND SNAILS 149 

Nanegal, Ecuador; Germain, 1907, Bull. Mus. National hist, nat., Paris, 
13, p. 54 — Nanegal, Rio Guallabamba, Ecuador (Rivet!). 
Dentellaria bourcieri (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 166 — Nane- 
gal, Ecuador (Wolf!). 

Isomeria bourcieri (Pfeiffer), Cousin, 1887, Bull. Soc. Zool. France, 12, pp. 254- 
255 — Los Puentes, near Gualea, Ecuador (Cousin!). Notes on ecology and 
color of animal. 

Pleurodonte (Isomeria) bourcieri (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 9, 
p. 94. 

Helix (Isomeria) bituberculata (Reeve), Germain, 1910, Miss. Arc de Mendien 
equatorial, 9 (3), pp. C.16-C.18. 

Range. — Central Ecuador in the Upper Esmeraldas, Napo and 
Pastaza drainages. Recorded localities are: Mindo, Gualea, Sigchos, 
Mt. Pichincha, Milpe and Nanegal on tributaries of the Rio Gualla- 
bamba; Mera and Puyo on the upper Rio Pastaza; Napo and Topo 
on the upper Rio Napo; and Otovalo. 

Material— Ecuador (CNHM 247, CNHM 40648, CNHM 95578) : 
Puyo, Rio Pastaza (CNHM 86668, ANSP 170725, Jackson 9338); 
Mindo (CNHM 117847, Jackson 4724); Sigchos, west of Latacunga 
(Jackson 9726) ; Mera (Jackson 5527) ; Milpe (Jackson 4821) ; Napo 
(Jackson 5290); Topo (Jackson 9988); Antisana (Jackson 10148); 
Tandayapa, west slope of Mt. Pichincha at 2,500 meters elevation 
(Jackson 11155, SMF 156320); Mt. Pichincha (Edinburgh) ; "Quito" 
(CNHM 50890, CNHM 102396, Zurich, Edinburgh). 

Diagnosis. — Basal lip with two small, close-set, pointed teeth, oc- 
casionally with accessory denticles between; lower palatal lip with 
single small crescentic tooth; upper palatal lip with larger spade-like 
tooth and marked indention behind the lip; umbilicus closed; surface 
nearly smooth with weak growth lines; periphery obtusely angulated 
to rounded; parietal callus very thin, occasionally with raised edge; 
lip white; color reddish-brown with an irregular pattern of yellow 
markings. Diameter 21.2-32.2 mm. (mean 26.0 mm.), H/D ratio 
0.562-0.715 (mean 0.636). 

Remarks. — The color pattern is the same found in Labyrinthus 
magdalenensis and immediately separates bourcieri from the other 
Isomeria. The position of the basal teeth and form of the lower pal- 
atal tooth relate bourcieri to other members of this group. The very 
elevated spire, strong upper palatal tooth and color, I consider to be 
secondary modifications. 

Most authors have called attention to Reeve's (loc. cit.) mislabeled 
figures, but only Germain in 1910 attempted to follow Reeve rather 



150 FIELDIANA: ZOOLOGY, VOLUME 50 

than considering them an obvious error. Reeve cited the Proceed- 
ings of the Zoological Society of London, 1852, and listed Pfeiffer as 
the author of the species. It is clear that he intended to follow Pfeif- 
fer's usage. The 1852 volume of the PZSL did not appear until 1854, 
giving Reeve's usage technical priority. Despite this, I have chosen 
to maintain the names in their Pfeifferean sense, since this will con- 
tribute to stability of nomenclature. 

Most of the available specimens were inadequately localized, and 
the few sets with good data contained only three or four specimens. 
Most of these were remnants of larger sets after material had been 
traded to other museums or collectors. The result is that no statis- 
tical treatment of the data was thought justified. Plotting of the 
diameter distribution revealed the following quite skewed distribu- 
tion, although the obesity index is much less distorted. The greater 
number of small shells may reflect the results of trading by collectors 
rather than the situation in natural populations. Only two speci- 
mens (Jackson 11155, SMF 156320) were accompanied by data on 
elevation (8,200 feet). 

Diameter in mm. 
22.0 24.0 26.0 28.0 30.0 32.0 
No. of specimens 8 13 15 24 2 2 

H/D ratio 
0.560 0.590 0.620 0.650 0.680 0.710 
No. of specimens 2 9 20 22 7 4 

Isomeria hartwegi (Pfeiffer, 1846). Figures 41f, 42b. 

Helix hartwegi Pfeiffer, 1846, Proc. Zool. Soc. London, 1845, pp. 126-127— 
El Catamaija, near Loxa, Ecuador (Hartweg!); Pfeiffer, 1848, Monog. 
helic. viv., 1, pp. 403-404; Reeve, 1852, Conch. Icon., Helix, pi. 104, 
fig. 575a-b; Pfeiffer, 1876, Monog. helic. viv., 7, p. 464; Dohrn, 1880, 
Jahrb. d. Malak. Gesell., 7, p. 86 — Synonymizes loxensis and hartwegi. 

Isomeria hartwegi (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 171; Cousin, 
1887, Bull. Soc. Zool. France, 12, p. 256. 

Isomeria loxensis (Miller), 1879, Malak. Blatt., n.f., 1, p. 118, pi. 12, fig. 1 — 
Catamayo Valley, Loja Prov., Ecuador at 3,000 feet elevation (Wolf!); 
Cousin, 1887, Bull. Soc. Zool. France, 12, p. 257. 

Helix (Isomeria) hartwegi (Pfeiffer), Pilsbry, 1889, Man. Conch. (2), 5, pp. 
153-154, pi. 45, figs. 15-16, pi. 64, fig. 26; Kobelt, 1893, Syst. Conch. Cab., 
I (12), 4, pp. 631-632, pi. 181, figs. 7-9 (plate issued in 1886). 

Pleurodonte (Isomeria) hartwegi (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 9, 
p. 94. 

Helix (Isomeria) loxensis (Miller), Reibisch, 1896, Abhl. naturwiss. Gesell. Isis, 
Dresden, 7, pp. 55-56 — Cerritos de Taura, Guayaquil, Ecuador (Wolf!). 



SOLEM: NEOTROPICAL LAND SNAILS 151 

Range. — Southern Ecuador from Loja at 3,000 feet elevation 
north to Cuenca (8,400 feet elevation) and west to Taura and Yagu- 
achi near Guayaquil. 

Material.— Ecuador (Edinburgh, Zurich, ANSP 45557, ANSP 
63579): La Galia, Yaguachi (CNHM 40647); Cuenca (CNHM 
40646); "Toza, 7,000." (Zurich ex Mousson, G. Wallis 1877). 

Diagnosis. — Basal lip with one or more very indistinct teeth or 
swellings; lower palatal lip with small conical tooth (occasionally 
absent); occasionally a peripheral notch results in a small swelling 
on the upper palatal lip; umbilicus rarely partly opened, usually 
closed; periphery nearly right angled ; parietal callus with raised edge; 
surface with fine grooves, but no malleations. Diameter 23-27 mm. 
(mean 25.9 mm.), H/D ratio 0.479-0.574 (mean 0.511). 

Remarks. — Pilsbry's copies (1889) of the type figures of hart- 
ivegi are very poor and totally misleading as to the form of the teeth 
and the color of the shell. It was probably these figures that led 
Reibisch {he. cit.) to separate hartwegi and loxensis. The latter seems 
to be a slightly umbilicated form with well-developed basal teeth. In 
all of the specimens seen, the umbilicus was completely closed and the 
basal teeth represented by very vague bumps or at most weak knobs. 
In one example from "Toza" the lower palatal tooth was absent and 
in the single example from Cuenca it was greatly reduced. 

The lower palatal tooth and more strongly carinated periphery 
easily separate /. hartwegi from the Colombian /. basidens and /. neo- 
granadensis. The larger, much heavier shell of /. juno also lacks the 
lower palatal tooth. 

The location of "Toza" is unknown and the position of "La Galia, 
Yaguachi" is uncertain since either the river near Guayaquil or the 
river near Zaruma could be correct. 

Group of Isomeria subelliptica 

The species agree in having a relatively widely open umbilicus 
for Isomeria, are generally of medium size (29-38 mm. in diameter)— 
although I. continua reaches nearly 50 mm. in maximum diameter and 
/. minuta is only 18.2 mm. — and have very reduced, simple dentition. 
Two of the species, /. morula and /. aloagana, are only known from 
their type collections and were not seen during this study; J. ano- 
donta and /. minuta are known from single specimens; /. subelliptica 
from three specimens; and only I. continua is represented in museum 
collections by more than a dozen individuals. /. morula may be an 



152 FIELDIANA: ZOOLOGY, VOLUME 50 

extreme variant of /. bituberculata, but the other species seem well 
characterized. 

Isomeria anodonta from Cajamarca, Peru at 6,000 feet elevation 
lacks any trace of apertural teeth and has a raised spire with obtusely 
angulated periphery. /. morula has a basal and an upper palatal 
tooth, probably a flatly rounded spire and scarcely any angulation 
to the periphery. /. aloagana from the Pacific slopes of Central 
Ecuador apparently has two weak basal tubercles, a moderately ele- 
vated spire and an acutely angulated periphery. J. continua from the 
Magdalena drainage in Caldas east to Villavicencio in Meta, Colom- 
bia at 3,400-4,400 feet elevation has no basal or palatal teeth, but 
usually a small parietal lamella, a normally elevated spire and an 
acutely angulated periphery. Its probable replacement in the Cauca 
drainage at 3,600-4,000 feet elevation (so far known only from Valle 
de Cauca), /. subelliptica, has a small parietal lamella, a flatly rounded 
spire and a very obtusely angulated periphery. /. minuta has a lower 
palatal tooth, a basal tooth and an acutely angulated periphery, and 
probably lives in the same area as J. continua. A provisional key to 
the species follows. 

KEY TO THE ISOMERIA SUBELLIPTICA GROUP 

1. No lower palatal tooth 2 

A prominent lower palatal tooth Isomeria minuta new species 

2. Periphery of body whorl acutely angulated 3 

Periphery of body whorl obtusely angulated 4 

3. Basal lip with small tubercles; Pacific Ecuador. 

Isomeria aloagana (Jousseaume, 1887) 
Basal lip without trace of teeth, often a small parietal lamella; Central Co- 
lombia Isomeria continua (Pfeiffer, 1854) 

4. No basal or palatal teeth present 5 

One basal and one upper palatal tooth Isomeria morula (Hidalgo, 1870) 

5. No parietal tooth; Peru Isomeria anodonta Pilsbry, 1949 

Small parietal lamella present; Cauca drainage, Colombia. 

Isomeria subelliptica (Mousson, 1869) 

Isomeria morula (Hidalgo, 1870) 

Helix martinii Bernardi, 1858 (not Pfeiffer, 1854), Jour, de Conchyl., 7, pp. 

93-94, pi. 1, fig. 3— Quito, Ecuador; Pfeiffer, 1868, Monog. helic. viv., 5, 

p. 382; Pfeiffer, 1876, Monog. helic. viv., 7, p. 442. 
Helix morula Hidalgo, 1870, Jour, de Conchyl., 18, p. 32 — new name for Helix 

martinii Bernardi, 1858, not Helix martini Pfeiffer, 1854. 
Isomeria martinii (Bernardi), Miller, 1878, Malak. Blatt., 25, p. 171. 
Isomeria morula (Hidalgo), Cousin, 1887, Bull. Soc. Zool. France, 12, pp. 257- 

258. 



SOLEM: NEOTROPICAL LAND SNAILS 153 

Helix (Isomeria) martinii Bernardi, Pilsbry, 1889, Man. Conch. (2), 5, p. 149, 

pi. 45, fig. 20. 
Pleurodonte (Labyrinthus) martinii (Bernardi), Pilsbry, 1894, Man. Conch. (2), 

9, p. 94. 

Diagnosis. — Basal lip with single prominent tooth; upper palatal 
lip with moderately prominent denticle; umbilicus widely open; pari- 
etal callus with thick, raised edge; periphery obtusely angulated; 
surface granulated with malleations on body whorl; lip white. Di- 
ameter 32 mm. (adapted from the original illustration and descrip- 
tion). 

Remarks. — Under Article 58, Section 10 of the International Code 
of Zoological Nomenclature, the names Helix martini Pfeiffer, 1854, 
and H. martinii Bernardi, 1858, are homonyms and Hidalgo's sub- 
stitute name must be used for the species, even though the Sumatran 
Elaphroconcha martini (Pfeiffer, 1854) belongs to a different family. 
During a brief study trip to Madrid, I was unable to locate any ma- 
terial of this species. The only specimens labeled as /. morula were 
misidentified /. bituberculata. Possibly, /. morula is a widely umbili- 
cated variety of bituberculata, but until specimens can be examined, 
its status will remain uncertain. 

Isomeria anodonta Pilsbry, 1949. Figure 44a-b. 

Isomeria anodonta Pilsbry, 1949, Nautilus, 62, (3), p. 100, pi. 6, figs. 3, a — 
Chaupo, Prov. Jaen, Dept. Cajamarca, Peru at 6,000 feet elevation 
(Carriker!). 

Range. — Known only from the type locality. 

Material— Peru: CAJAMARCA— Chaupo, Prov. Jaen (ANSP 

165202, holotype). 

Diagnosis. — No apertural teeth ; umbilicus widely open, contained 
8.9 times in the diameter; periphery obtusely angulated; parietal 
callus with broad raised edge; surface with prominent radial growth 
striae, malleated on body whorl; lip brown. Diameter 39.2 mm., 
H/D ratio 0.517, with 4% whorls. 

Remarks.— The elevated spire and lack of dentition immediately 
separate anodonta from the other openly umbilicated forms. Only 
the holotype, a rather worn, dead specimen, is known. Of the other 
Peruvian species, /. meobambensis has a closed umbilicus and a large 
lower palatal tooth, while in /. stoltzmanni the umbilicus is partly 
closed, the periphery acutely angulated, and there is distinct palatal 
dentition. 




Fig. 43. Isomeria aloagana. Copied from Bull. Soc. Zool. France, 12, pi. 3, 
figs. 6, 7 (1887). a, base; b, side. 



154 






SOLEM: NEOTROPICAL LAND SNAILS 155 

Isomeria aloagana Jouseaume, 1887. Figure 43a-b. 

Isomeria aloagana Jousseaume, 1887, Bull. Soc. Zool. France, 12, pp. 179-180, 
pi. 3, figs. 6-7 — trail from Aloag to Rio Toachi, Canton of Megia, Prov. 
Pichincha, Ecuador (Cousin!); Cousin, 1887, op. cit., 12, p. 254. 

Helix (Isomeria) aloagana (Jousseaume), Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 139-140, pi. 43, figs. 48-49. 

Pleurodonte (Isomeria) aloagana (Jousseaume), Pilsbry, 1894, Man. Conch. 
(2), 9, p. 94. 

Diagnosis. — Basal lip with two inconspicuous tubercles; no pari- 
etal or palatal teeth; umbilicus partly covered by reflection of lip; 
periphery right angled; parietal callus very thin, without raised edges; 
surface minutely granulated with fine, radial growth lines. Diameter 
35-38 mm., height 16-17 mm. (modified from original description). 

Remarks. — The absence of any parietal and palatal teeth and the 
presence of two small basal tubercles are the main identifying fea- 
tures. Conceivably, this species is based on young individuals of 
a dwarf race of Isomeria kolbergi or possibly of I. jacksoni. The 
presence of fine granulations is much more characteristic of the oreas 
group. 

No specimens could be located. The types are not in the Jous- 
seaume collection in Paris. Birds from Aloag were taken from 7,800- 
9,570 feet, but where the specimens of J. aloagana came from is un- 
known. Probably they were taken somewhere in the upper Pilat6n 
or Quitasol valleys. 

Isomeria continua (Pfeiffer, 1854). Figure 44c-d. 

Helix continua Pfeiffer, 1854 (June), in Reeve's Conch. Icon., Helix, pi. 184, 
fig. 1270— Province of Ocafia, Colombia (Schlim!); Pfeiffer, 1854 (Novem- 
ber), Proc. Zool. Soc. London, 1853, p. 128; Pfeiffer, 1859, Monog. helic. 
viv., 4, p. 308; Pfeiffer, 1876, Monog. helic. viv., 7, p. 464. 

Helix (Isomeria) continua Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, p. 137, 

pi. 46, fig. 27. 
Helix (Isomeria) peritropis Pilsbry, 1889, Man. Conch. (2), 5, pp. 140-141, 

pi. 63, figs. 10-13— Bogota, Colombia. 
Pleurodonte (Isomeria) peritropis (Pilsbry), Pilsbry, 1894, Man. Conch. (2), 

9, p. 94. 
Pleurodonte (Isomeria) continua (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 

9, p. 94. 
Isomeria continua (Pfeiffer), Pilsbry, 1935, Proc. Acad. Nat. Sci., Philadelphia, 

87, p. 83 — region of Villavicencio, Colombia (Apolinar Maria!). 

Range. — Central Colombia between Manizares, Caldas and Villa- 
vicencio, Meta. Described from "Province of Ocafia." 



156 



FIELDIANA: ZOOLOGY, VOLUME 50 



Material.— Colombia: "Bogota (Edinburgh, SMF 172167, ANSP, 
ANSP 63585, ANSP 45555, ANSP 33134 types of peritropis Pilsbry). 
CALDAS— Manzanares at 1,340 meters (MCZ 145206). META- 
CUNDINAMARCA— Guayabetal at 1,030 meters (MCZ 143365) ; 




Fig. 44. Shells of: a-b, Isomeria anodonta, Chaupo, Jaen, Peru, ANSP 165202. 
Holotype (a, side; b, aperture); c, Isomeria continua, Bogota, Colombia. Edin- 
burgh; d, Isomeria continua, Bogota, Colombia, ANSP 33134. Holotype of peri- 
tropis Pilsbry, 1889. 



Pipiral on road from Bogota to Villavicencio (Jackson 6105) ; region 
of Villavicencio (ANSP 164559). 

Diagnosis. — Basal and palatal lip without dentition; parietal wall 
often with small ovate denticle; umbilicus widely open; periphery 
acutely angulated; spire normally elevated; lip white; parietal callus 
with narrow, strongly raised edge; surface with very weak, fine, 
growth lines. Diameter 29.6-49.7 mm. (mean 36.2 mm.), H/D ratio 
0.433-0.523 (mean 0.471). 

Remarks. — Apparently this is either highly variable in size, or two 
species are being confused. The type of continua (diameter 40.2 mm.), 
and three shells from "Bogota" (Edinburgh, SMF 172167, ANSP 
45555) (diameters 43.6, 43.5 and 49.7 mm., respectively) are very 



SOLEM: NEOTROPICAL LAND SNAILS 157 

large. Another specimen from "Bogota" is 39.9 mm. in diameter. 
The other specimens range from 29.6-35.6 mm. in diameter, includ- 
ing the types of peritropis. The data accompanying the few localized 
shells gives no indication of the ecological conditions and the larger 
shells are not known from an exact locality. 

The parietal tooth is present in nine of the ten small and none of 
the four large specimens examined, although found in the type of 
continua. 

Only two localities included altitudinal data. The range of 3,375- 
4,390 feet is one of the lowest known for Isomeria. 

Isomeria minuta new species. Figure 45a-d. 

Diagnosis. — The smallest known species of Isomeria, diameter 
18.2 mm., with broadly open umbilicus (D/U ratio 5.7), acutely an- 
gulated periphery, elevated spire, one large basal tooth and a single 
crescentic lower palatal tooth with posterior indention. The open 
umbilicus, shell form, parietal lip and sculpture relate this to the 
J. subelliptica complex, but the presence of a lower palatal tooth with 
posterior indention and a large basal tooth at once separate it as a 
distinct species. 

Holotype. — Senckenberg Museum, Frankfurt-am-Main number 
172174. Sierra de Mariquita at 2,170 meters elevation. Probably 
this is a portion of the Cordillera Central of the Andes near the Cal- 
das-Tolima border above the town of Mariquita, Tolima, Colombia. 

Description. — Shell very small, with 4% normally coiled whorls. 
Spire markedly and evenly elevated, apex protruding, sides of spire 
with faintly concave outline, although individual whorls distinctly 
rounded, H/D ratio 0.489. Apex and early spire somewhat worn, 
without distinctive sculpture, lower spire with prominent growth 
wrinkles and minute scattered granulations. Periphery acutely an- 
gulated, rounded on edge, flattened immediately above and below 
angulation. Color light greenish-yellow-brown with lighter flecks 
and streaks. Lip white. Umbilicus widely open, very slightly nar- 
rowed by expansion of parietal and basal lips, contained 5.7 times in 
the diameter, margins rounded. Aperture subquadrangular, mod- 
erately deflected, inclined about 50° from shell axis. Parietal wall 
with narrow, nearly straight, elevated callus lip, but no dentition. 
Basal-parietal margin sinuated, with basal lip nearly straight and a 
broad, high, rounded knob marking the outer edge. Lower palatal lip 
with single crescentic lamella marked by a weak posterior indention 



158 



FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 45. Isomeria minuta: Sierra de Mariquita, Colombia, SMF 172174. Holo- 
type. a, top; b, base; c, side; d, aperture. Scale lines equal 10 mm. 



and a slight lateral buttress extending up to periphery. Peripheral 
lip distinctly angulated, lower portion of upper palatal lip straight, 
upper part curved. Lower palatal and basal lips moderately to 
strongly reflected, upper palatal lip only slightly reflected. Height 
of holotype 8.9 mm., diameter 18.2 mm. 

Remarks. — The only data accompanying the single shell was 
"S. de Mariquita, 2170 m." The town of Mariquita, Tolima lies 
17 km. west of Honda at the base of the Cordillera Central in the 
Magdalena drainage. Although the "Sierra de Mariquita" does not 
appear on any available map, this could be a local name or an early 
collector's attempt to designate a portion of the mountains above 
the town. Certainly this area would be the logical place to search 
for I. minuta. 

As in the case of J. inexpectata, this species shows characters refer- 
able to both Labyrinthus and Isomeria and is thus described despite 
the availability of only a single example and the uncertain type local- 
ity. The large basal tooth at the outer edge of the basal lip and cres- 
centic lower palatal tooth with posterior indention are typical of 



SOLEM: NEOTROPICAL LAND SNAILS 



159 




Fig. 46. 
bia. Zurich. 
10 mm. 



Isomeria subelliptica: Bagua (=Buga), 4,000 feet elevation, Colom- 
Holotype. a, top; b, base; c, side; d, aperture. Scale lines equal 



Labyrinthus and not seen in Isomeria, except for the large indented 
lower palatal tooth of I. globosa. The lack of any parietal dentition, 
the straight parietal lip (identical with that found in I. continua) , the 
widely open umbilicus and sculpture of growth wrinkles and fine 
granulations are as in the I. subelliptica complex. 

The probable geographic range lies within the range of I. continua 
and the altitude of 7,125 feet combines with the characters listed 
above to place I. minuta with the I. subelliptica complex rather than 
in Labyrinthus. The characters of I. minuta suggest that the tran- 
sition from Labyrinthus to Isomeria (or vice versa) may have hap- 
pened several times. 



Isomeria subelliptica (Mousson, 1869). Figure 46a-d. 

Helix subelliptica Mousson, 1869, Malak. Blatt., 16, pp. 170-171 — Bugua 
(=Buga?), Amazonas at 4,000 feet elevation (Wallis!); Pfeiffer, 1875, 
Novit. Conch., 4, pp. 117-118, pi. 127, figs. 4-6; Pfeiffer, 1876, Monog. 
helic. viv., 7, p. 464. 



160 FIELDIANA: ZOOLOGY, VOLUME 50 

Helix (Isomeria) subelliptica Mousson, Pilsbry, 1889, Man. Conch. (2), 5, 
p. 139, pi. 46, figs. 28-30; Kobelt, 1894, Syst. Conch. Cab., I (12), 4, p. 628, 
pi. 180, figs. 8-11. 

Pleurodonte (Isomeria) subelliptica (Mousson), Pilsbry, 1894, Man. Conch. (2), 
9, p. 94. 

Range. — Cauca River Valley in Valle de Cauca, Colombia. 

Material.— Colombia: "Ocanna" (Zurich). VALLE DE CAUCA 
—gardens of Cali at 1,100 meters (USNM 251176); Buga (=Bugua) 
at 4,000 feet elevation (Zurich, holotype of subelliptica). 

Diagnosis. — Basal and palatal lips without teeth; parietal wall 
with small crescentic lamella transversely situated above periphery; 
umbilicus widely open, lips covering only a small portion; periph- 
ery obtusely angulated, spire flatly rounded, lip brownish; parietal 
callus with narrow, sharply raised edge; surface with fine, crowded, 
growth striae. Diameter 29.0-34.6 mm. (mean 30.9 mm.), H/D 
ratio 0.456-0.575 (mean 0.507). 

Remarks. — Through a curious typographical error, the major di- 
ameter has been recorded in the literature as 38 mm., although the 
minor diameter was listed correctly as 23 mm. Actual measure- 
ments of the holotype are — major diameter 29.2 mm. and minor di- 
ameter 23.2 mm. The small size, very wide umbilicus (D/U ratio 
5.9-11.9) and obtusely angled periphery separate subelliptica from 
1. continua and /. anodonta. The single shell from Cali is atypical 
in having a narrower umbilicus, higher spire and thicker, much more 
strongly reflected lip. Both localized specimens were taken between 
3,600 and 4,000 feet elevation. 

Group of Isomeria meobambensis 

The species are of medium size, diameter 30-42 mm., with totally 
closed umbilicus and a right-to-obtusely angulated periphery. They 
are known from Southern Ecuador and Peru. Usually only the sur- 
face has noticeable radial growth ribs, but /. meyeri and J. gealei 
show marked malleations near the periphery. I. meyeri completely 
lacks dentition. /. gealei and /. aequatoria agree in having a mid- 
basal, transversely situated lamella (larger in aequatoria), a promi- 
nent lower palatal tooth (very large and transversely twisted in 
gealei), and the upper palatal lip with a weak (aequatoria) to promi- 
nent (gealei) triangular knob forming the upper edge of a peripheral 
notch. /. meobambensis lacks basal and upper palatal dentition, hav- 
ing only a single lower palatal tooth with a lateral extension reaching 
the periphery (fig. 47b) that is unique in Isomeria. 



SOLEM: NEOTROPICAL LAND SNAILS 161 

The range of /. meyeri (Ostlichen Cordillera von Ecuador) is un- 
known; J. meobambensis has been reported only from Moyobamba, 
San Martin, Peru; /. gealei from Malacatos, southern Ecuador; and 
I. aequatoria from the upper Chanchan drainage on the Pacific slopes 
of central Ecuador. 

A key to the species follows. 

KEY TO THE ISOMERIA MEOBAMBENSIS GROUP 

1. Aperture with denticles 2 

Aperture without denticles Isomeria meyeri (Strubell, 1894) 

2. Basal tooth present; lower palatal tooth a simple or twisted lamella 3 

Basal tooth absent; lower palatal tooth with upper lateral extension. 

Isomeria meobambensis (Pfeiffer, 1857) 

3. Lip iridescent; basal tooth very small; body whorl with malleations. 

Isomeria gealei (E. A. Smith, 1877) 
Lip brown; basal tooth large; body whorl without malleations. 

Isomeria aequatoria (Pfeiffer, 1860) 

Isomeria meobambensis (Pfeiffer, 1857). Figure 47a-b. 

Helix meobambensis Pfeiffer, 1857, Proc. Zool. Soc. London, 1856, p. 328 — 

Moyobamba, Peru (Porte!); Pfeiffer, 1859, Monog. helic. viv., 4, p. 243; 

Pfeiffer, 1876, Monog. helic. viv., 7, p. 361. 
Helix (Isomeria) meobambensis Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, 

p. 144. 
Pleurodonte (Isomeria) meobambensis (Pfeiffer), Pilsbry, 1894, Man. Conch. 

(2), 9, p. 94; Haas, 1951, Fieldiana: Zool., 31 (46), pp. 511-512— Peru 

(type lot specimen of /. anestia Pilsbry, 1949). 
Isomeria anestia Pilsbry, 1949, Nautilus, 62, (3), pp. 99-100, pi. 6, figs. 4, 4a, 4b 

— probably Peru. 
Labyrinthus (Isomeria) meobambensis (Pfeiffer), Weyrauch, 1964, Acta Zool. 

Lilloana, 20, p. 60. 

Range. — Known only from the type locality. 

Material— Peru (SMF 141090, CNHM 30704, type lot of anestia 
Pilsbry, 1949; CNHM 40640; ANSP 184497, types of anestia Pilsbry, 
1949) : SAN MARTIN— Moyobamba (Zurich, Edinburgh ex Cum- 
ing, Brit. Mus., probably cotypes). 

Diagnosis. — Basal lip straight, without teeth or swelling; lower 
palatal lip with a small conical tooth that has a high upper extension 
reaching periphery; umbilicus completely covered; periphery nearly 
right angled; parietal callus very thin, upper and lower edges slightly 
raised; surface with rather heavy radial ribs and grooves. Diameter 
30.6-37.2 mm. (mean 34.3 mm.), H/D ratio 0.482-0.556 (mean 0.529). 

Remarks. — Pfeiffer's species was never figured and its identifica- 
tion with anestia Pilsbry is based on material in older collections 



162 FIELDIANA: ZOOLOGY, VOLUME 50 

labeled as meobambensis. They match the types of anestia and the 
description of meobambensis perfectly. 

The peculiar lower palatal tooth with lateral extension that reaches 
the periphery through an extension is unique among Isomeria. When 
combined with the relatively strong radial sculpture, there is no spe- 
cies with which it can be confused. The presently unclassifiable 
/. equestrata Moricand, 1858 (see p. 194) may be based on a slightly 
subadult specimen of J. meobambensis. 

Variation in part of the type set is summarized in Table XIII. 
Isomeria gealei (Smith, 1877). Figure 47c-d. 

Helix (Isomeria) gealei Smith, 1877, Proc. Zool. Soc. London, 1877, pp. 361- 
362, pi. 39, fig. 9a, b— Malacatos, South Ecuador (Geale!); Cousin, 1887, 
Bull. Soc. Zool. France, 12, p. 255; Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 149-150, pi. 61, figs. 4-5. 

Helix gealei Smith, Dohrn, 1886, Syst. Conch. Cab., I (12), 4, pp. 626-627, 
pi. 180, figs. 5-6. 

Isomeria gealei (Smith), Miller, 1879, Malak. Blatt., n.f., 1, p. 193; Cousin, 
1887, Bull. Soc. Zool. France, 12, p. 255. 

Pleurodonte (Isomeria) gealei (Miller), Pilsbry, 1894, Man. Conch. (2), 9, p. 94. 

Range. — Cordillera de Zamura, south of Loja, southern Ecuador. 

Material— Ecuador (CNHM 40644, USNM 125909, ANSP 33135, 
Zurich, Edinburgh) : Malacatos (Jackson 7506) ; Toza, 7,000 feet ele- 
vation (Zurich, ex Mousson, Wallis, 1877) . 

Diagnosis. — Basal lip with one low diagonal tooth; lower palatal 
lip with high, brownish white, transversely twisted lamella bordering 
a deep peripheral notch; upper edge of peripheral notch protruded to 
form a small triangular knob; umbilicus completely covered; parietal 
callus thin with thickened, raised edge; periphery acutely angulated 
with protruding keel; surface with faint growth striae and grooves, 
moderately heavily malleated on body whorl; lip purplish tinted and 
iridescent. Diameter 33.5-41.2 mm. (mean 36.0 mm.), H/D ratio 
0.505-0.557 (mean 0.531). 

Remarks. — The purplish, iridescent lip with the white-tipped, 
transversely twisted lower palatal lamella immediately identifies this 
species. No other Isomeria can be confused with it. The upper pal- 
atal knob is very much like that in Labyrinthus otostomus. 

Malacatos is on the slopes of the Cordillera de Zamura below Loja 
and the type specimens probably came from between 5,000 and 6,500 
feet elevation. The location of Toza is unknown. 




Fig. 47. Shells of: a, Isomeria meobambensis, Peru, CNHM 40640. Side; 
b, Isomeria meobambensis, Peru, ANSP 184497. Holotype of anestia Pilsbry, 1949. 
Aperture; c-d, Isomeria gealei, Ecuador, CNHM 40644 (c, side; d, aperture); 
e-f, Isomeria aequatoria, 6 miles below Huigra, Ecuador, ANSP 148483 (e, side; 
/, aperture). Scale lines equal 10 mm. 



163 



164 FIELDIANA: ZOOLOGY, VOLUME 50 

I so hut in aequatoria (Pfeiffer, 1860). Figure 47e-f. 

Helix aequatoria Pfeiffer, 1860, Proc. Zool. Soc. London, 1860, pp. 133-134, 
pi. 50, fig. 6— Ecuador (Fraser!); Pfeiffer, 1868, Monog. helic. viv., 5, 
p. 314; Pfeiffer, 1876, Monog. helic. viv., 7, p. 361. 

Isomeria aequatoria (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 170; Cousin, 
1887, Bull. Soc. Zool. France, 12, pp. 253-254. 

Helix (Isomeria) aequatoria Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 150-151, pi. 48, figs. 44-46; Kobelt, 1893, Syst. Conch. Cab., I (12), 
4, p. 629, pi. 180, figs. 12-13 (plate issued in 1886); Reibisch, 1896, AbhI. 
naturwiss. Gesell. Isis, Dresden, 7, p. 55 — Cayandelet, western Mts., 
Ecuador (Wolf!). 

Pleurodonte (Isomeria) aequatoria (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 
9, p. 94. 

Range. — Central Ecuador in the upper Chanchan drainage. The 
only recorded localities are Huigra and Cayandeled. 

Material—Ecuador (CNHM 40638, ANSP 78358, MCZ, ZMA, 
Edinburgh, CNHM 132555): six miles below Huigra, Chanchan 
River (ANSP 148483) ; "Quito" (ANSP 30644, MCZ 88157, Zurich). 

Diagnosis. — Basal lip with high conical, transversely slanted la- 
mella; lower palatal lip with higher, narrower tooth; upper palatal 
lip with low triangular swelling just above periphery; umbilicus com- 
pletely covered; periphery right or obtusely angled; lip tinged with 
brown; parietal callus thin with slightly raised edge; surface with fine 
growth lines and grooves. Diameter 32.0-39.8 mm. (mean 35.7 mm.), 
H/D ratio 0.556-0.609 (mean 0.590). 

Remarks. — The form of the teeth is nearly identical to that of 
/. gealei, but the different color of the lip, transverse lower palatal 
tooth, malleated body whorl, and greater angulation of the latter, 
immediately separate the two species. J. triodonta could be confused 
with J. aequatoria, but the former has two basal teeth, a second pal- 
atal tooth, usually a partially open umbilicus and the body whorl 
shows distinct malleations. 

The two known localities are both in the upper Chanchan drain- 
age on the Pacific slopes. Ornithological collecting at these places 
ranged from 2,600-7,000 feet elevation. The altitudinal range of 
J. aequatoria is unknown. 

Isomeria meyeri (Strubell, 1894) 

Helix (Isomeria) meyeri Strubell, 1894, Syst. Conch. Cab., I (12), 4, pp. 693- 
694, pi. 198, figs. 3-4 — Ostlichen Cordillera von Ecuador. 






SOLEM: NEOTROPICAL LAND SNAILS 165 

Diagnosis. — Aperture without teeth; umbilicus closed by basal 
and parietal lips which flatten into a broad callus; periphery right 
angled; surface heavily malleated; parietal callus thin; lip yellowish 
white. Diameter 36 mm., height 21 mm. 

Remarks. — The heavy malleations on the shell and total lack of 
apertural teeth separate /. meyeri from other members of this group. 
The form of the basal lip is very similar to that found in /. aequatoria, 
hence its placement with this complex. No exact locality has been 
reported for this species and the type specimen could not be located. 
A slightly shortened translation of the detailed original description 
follows: 

Shell imperforate, compressed, transversely widened, solid, but not exception- 
ally thick; surface with transverse growth wrinkles and fine, somewhat wavy, 
microscopic spiral lines; color yellow-brown, with broad, wavy chestnut brown 
stripes that coalesce on base of shell. Spire flatly conical with smooth, rather 
pointed, whitish apex. Whorls four, sutures impressed and finely crenulated; 
upper whorls weakly rounded, slowly increasing in width, body whorl inflated, 
flattened for a short distance below the suture, shouldered, then rounded on 
base to the impressed umbilical callus. Aperture deflected, egg-shaped, bluish 
inside with a light peripheral zone. Lip white, thick, reflected, upper and basal 
margins almost parallel, outer margin abruptly rounded, basal margin elon- 
gated, ascending obliquely and forming a slightly curved, hardly widened 
blunt fold when covering the umbilicus. Parietal callus thin. 

Recognition of this species should be quite easy, since the combina- 
tion of no teeth, totally closed umbilicus and malleated shell is not 
matched by any other species of Isomeria. 

Group of Isomeria oreas 

Normally these are large shells (mean diameter over 39 mm.), 
whose combinations of characters vary so greatly that the group can- 
not be characterized concisely. The changes in each shell feature 
from species to species are small enough that no separation into spe- 
cies groups seems necessary, yet the total range of variation for all 
species is large enough that diagnostic separation from the /. meo- 
bambensis complex is difficult. 

A series of alterations in form and structure can be traced between 
the larger and smaller types that cover most of the included species. 
Conceivably, as in Labyrinthus, it is most probable that changes from 
the smaller to the larger are the more logical assumption. For dis- 
cussion purposes, however, either way of describing the changes is 
valid. I've chosen to start with the very large /. oreas and trace the 
pattern of changes then observed in the other, smaller species. 

/. oreas has a large shell with very obtusely angled periphery, an 
open umbilicus with clearly visible internal groove, weak malleations 



166 FIELDIANA: ZOOLOGY, VOLUME 50 

on the later whorls, and prominent parietal and basal teeth. In the 
slightly smaller J. kolbergi the umbilicus is distinctly narrower al- 
though the internal groove is still visible, the parietal tooth is miss- 
ing, the malleations are more prominent and the periphery is more 
angulated. /. triodonta has an even narrower umbilicus, but possesses 
additional apertural teeth and heavier malleations with a sharper 
peripheral angulation. The small Peruvian /. stoltzmanni has a wider 
umbilicus than kolbergi, but lacks the malleations, is finely granulated 
and retains the lower palatal tooth. This is similar to /. jacksoni, 
which differs in having a nearly closed umbilicus and lacks both mal- 
leations and granulations. A slight alteration in pattern is seen in 
three species that have a secondary calcareous plate increasing the 
closure of the umbilicus. /. cymatodes has a parietal tooth, is very 
heavily malleated and has an obtusely rounded periphery. In Colom- 
bia, /. scalena with no apertural teeth and weak malleations, plus 
/. fordiana with only a weak lower palatal tooth and no malleations 
on the shell, have the same umbilical closure. This leaves two spe- 
cies that are rather distinctive. /. aequatoriana normally has the 
umbilicus closed by expansion of the basal and parietal lips and lacks 
all malleations, although very finely granulated on the surface. /. glo- 
bosa, which extends into the coastal regions of Ecuador, has a narrow 
to closed umbilicus, a finely granulated surface and an extremely 
large lower palatal tooth with a marked posterior indention. The 
posterior indention is unique in Isomeria, although common in the 
isodon and raimondii series of Labyrinthus. Since /. globosa is the 
only truly lowland species of Isomeria, it is an intriguing possibility 
that the tooth structure is an attempt to narrow the aperture against 
predators found in lowland areas. Tooth development in /. globosa 
may parallel the tooth development in Labyrinthus. 

Distributional data are sparse to abundant. Surprisingly, although 
44 specimens of /. triodonta were found in museum collections, no 
locality is known for this species. /. oreas has a wide range in the 
Cauca and Magdalena drainages of Colombia. I. scalena is known 
only from the headwaters of the Rio Magdalena drainage and I. fordi- 
ana has been reported from Marmato and (dubiously) Ocana. J. 
stoltzmanni in Cajamarca, Peru is the southernmost species of Iso- 
meria; I. globosa ranges from southern Colombia to southern Ecuador 
in the Pacific drainage and has crossed over into the Upper Ama- 
zonian drainage; and /. aequatoriana is found only in the upper 
Amazonian areas. The remaining species, /. cymatodes, I. kolbergi 
and /. jacksoni have the same distribution, living in the Upper Rio 
Esmereldas drainage and Upper Amazonian drainage. 



SOLEM: NEOTROPICAL LAND SNAILS 167 

KEY TO THE ISOMERIA OREAS COMPLEX 

1. Lower palatal tooth very small or absent, never marked by a deep posterior 

indention 2 

Lower palatal tooth very large, clearly marked by a deep posterior indention. 

Isomeria globosa (Broderip, 1832) 

2. No parietal tooth present 4 

A distinct parietal tooth present 3 

3. Umbilicus moderately open with columellar groove visible; surface with few 

weak malleations near periphery; Colombia. . . .Isomeria oreas (Koch, 1844) 
Umbilicus nearly to completely closed by an accessory plate extending from 
lips; heavy malleations on body whorl; Ecuador. 

Isomeria cymatodes (Pfeiffer, 1852) 

4. Lip with one or more teeth 5 

Lip without teeth Isomeria scalena (von Martens, 1881) 

5. Surface of body whorl moderately to heavily malleated; periphery acutely 

angled 6 

Surface of body whorl without malleations; periphery usually right or obtusely 
angled 7 

6. Only lower palatal tooth present; umbilicus distinctly open; lip white. 

Isomeria kolbergi Miller, 1878 (Ecuador) OR 

Isomeria fauna (Philippi, 1851) (Colombia) (see p. 194) 

Basal, lower palatal and upper palatal teeth; umbilicus reduced to a slit or 

closed; lip with brown tints Isomeria triodonta (Orbigny, 1835) 

7. Umbilicus closed or a very narrow slit 8 

Umbilicus open, contained 12-14 times in the diameter; Peru. 

Isomeria stoltzmanni (Lubomirski, 1879) 

8. Basal and parietal lips not expanded to form a callus completely closing um- 

bilicus; diameter less than 46 mm 9 

Basal and parietal lips expanding to form a smooth callus that completely 
closes umbilicus (rarely leaving a microscopic lateral crack) ; diameter usually 
much more than 45 mm Isomeria aequatoriana (Hidalgo, 1867) 

9. Shell surface with microscopic granulations; Colombia. 

Isomeria for diana (Pilsbry, 1889) 
Shell surface without such granulations; Ecuador. 

Isomeria jacksoni Solem, 1966 

Isomeria oreas (Koch, 1844). Figures 48a-b, 49a. 

Helix oreas Koch, 1844, in Philippi's Abbild. Besch. neuer Conchy., 1 , pp. 151- 

152, Helix, pi. 5, fig. 2 — mountains of Colombia; Pfeiffer, 1848, Monog. 

helic. viv., 1, pp. 400-401; Pfeiffer, 1851, Syst. Conch. Cab., I (12), 2, 

pp. 55-56, pi. 75, figs. 1-3 (plate issued in 1849); Reeve, 1852, Conch. 

Icon., Helix, pi. 99, fig. 546; Pfeiffer, 1853, Monog. helic. viv., 3, p. 257; 

Pfeiffer, 1859, Monog. helic. viv., 4, p. 308; Pfeiffer, 1868, Monog. helic. 

viv., 5, p. 412; Mousson, 1873, Malak. Blatt., 21, p. 2; Pfeiffer, 1876, 

Monog. helic. viv., 7, p. 464. 
Helix procera Pfeiffer, 1854 (June), in Reeve's Conch. Icon., Helix, pi. 184, 

fig. 1273 — Antioquia, Colombia; Pfeiffer, 1854 (November), Proc. Zool. 

Soc. London, 1853, p. 127; Pfeiffer, 1859, Monog. helic. viv., 4, p. 308; 

Pfeiffer, 1868, Monog. helic. viv., 5, p. 412; Pfeiffer, 1876, Monog. helic. 

viv., 7, p. 464. 



168 FIELDIANA: ZOOLOGY, VOLUME 50 

Helix (Isomeria) oreas Koch, von Martens, 1885, Conch. Mitteil., 2 (5-6), 
p. 156 — IbaguS, Colombia at 1,280 meters elevation (Stiibel!); Pilsbry, 
1889, Man. Conch. (2), 5, pp. 136-137, pi. 45, figs. 11-12, 17-19, pi. 48, 
fig. 43; Dohrn, 1894, Syst. Conch. Cab., I (12), 4, p. 627, pi. 180, fig. 7— 
monstrosity. 

Pleurodonte (Isomeria) oreas (Koch), Pilsbry, 1894, Man. Conch. (2), 9, 
pp. 93-94. 

Isomeria oreas (Koch), Piaget, 1912, Mem. Soc. neuchateloise Sci. nat., 5, 
p. 257 — Angelopolis, near Titiribf, Prov. Antioquia, Colombia (Fuhr- 
mann!); Pilsbry, 1935, Proc. Acad. Nat. Sci., Philadelphia, 87, p. 83— 
Calarca, Colombia (Apolinar Maria!). 

Isomeria oreas var. parvula Piaget, 1912, loc. cit., 5, p. 257, pi. 9, fig. 8 — Angel- 
6polis, near Titiribf, Prov. Antioquia, Colombia at 1,970 meters elevation 
(Fuhrmann!). 

Range. — Colombia, valley of the Rio Cauca and Cordillera Central 
from Frontino or Angelopolis, Antioquia south to Popayan, Cauca. 
Also at Villavicencio, Meta. Recorded from 3,900-9,500 feet elevation. 

Material— Colombia (CNHM 245, CNHM 40636, ANSP 30641, 
USNM 307678, USNM 316112-316115, ZMA, Zurich) : CALDAS— 
Salamina (Jackson 6305, USNM 518434); Mt. Quindiu (Paris); Mar- 
mato (ANSP 9272, ANSP 30642); Calarca (ANSP 164560) ; Valle de 
Magdalena at 1,200 meters (MCZ 145205). ANTIOQUIA (Brit. 
Mus., types of procera Pfeiffer) — Tamesis (Jackson 6311); ?Frontino 
(Zurich ex Wallis 1881). TOLIMA— Mt. Tolima (SMF). VALLE 
DE CAUCA— Rio Paila Valley, 1,800 meters, Central Cordillera 
(USNM 251172). CAUCA (ANSP 91219, Edinburgh)— Rio Palo 
headwaters, 2,900 meters, Central Cordillera (USNM 251174) ; Po- 
payan (SMF) ; La Cumbre, near Popayan (ANSP 132448) ; Quilichao 
(Edinburgh). HUILA— Rio Paez Valley, 2,900 meters, Central Cor- 
dillera (USNM 251173). CUNDINAMARCA— ?Bogota (Zurich ex 
Wallis 1872, Paris) . META— ?Sonora (Zurich) ; Caiio Grande, Villa- 
vicencio (MCZ 146366). "Ecuador" (ANSP 63587, Zurich). 

Diagnosis. — Parietal wall with small but prominent crescentic 
tooth; lower palatal lip with small conical tooth; periphery obtusely 
angulated; umbilicus widely open with noticeable columellar groove; 
surface with rather fine radial striae, weakly malleated near periph- 
ery; parietal callus thin or with prominent raised edge; lip white, edge 
brownish; color dull liver brown. Diameter 43.0-72.4 mm. (mean 
57.3 mm.), H/D ratio 0.450-0.597 (mean 0.528). 

Remarks. — Germain recorded J. oreas from Horongo, Nanegal and 
Cordillera de Intag in the upper Rio Esmereldas drainage of Ecuador, 
but his records are erroneous. The specimens are preserved in the 



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FIELDIANA: ZOOLOGY, VOLUME 50 




Fig. 48. Shells of: a, Isomeria oreas, "Ecuador." Zurich, large; b, I. oreas, 
Frontino, Antioquia, Colombia. Zurich, small; c, Isomeria kolbergi, Los Puentes, 
Ecuador, CNHM 117850; d, Isomeria triodonta, Ecuador, CNHM 40641. Scale 
line equals 10 mm. 



Museum National d'Histoire Naturelle, Paris and are a mixture of 
two species — I. kolbergi and I. cymatodes (see below). 

Most of the valid records are from the Cordillera Central of Co- 
lombia. Two records from the west side of the Cauca River, the 
material from Villavicencio, Dept. Meta and two questionable local- 
ities in the Mousson material (Sonora, Dept. Meta and Frontino, 
Dept. Antioquia) are the only exceptions. Six sets or literature rec- 
ords were accompanied by elevation data, ranging between 3,900- 
9,500 feet elevation. No obvious correlation between size and ele- 
vation could be seen, and only a tenuous correlation between size 
and locality. The specimens from Antioquia were less than 51 mm. 
in diameter, except for some from Angelopolis reported by Piaget 
(loc. cit.) . The small specimens were called form parvula Piaget, 1912. 
Possibly this will be shown to be a valid geographic race, but too 
little material is currently available. Unfortunately, the only large 
set seen (ANSP 91219) was not specifically localized. Size variation 




Fig. 49. Apertures of: a, Isomeria oreas, "Ecuador." Zurich, large; b, Iso- 
meria kolbergi, Los Puentes, Ecuador, ANSP 61696. Holotype oifaunus ritchieana 
Pilsbry, 1889; c, Isomeria triodonta, locality uncertain. Madrid. Scale lines equal 
10 mm. 



171 



172 FIELDIANA: ZOOLOGY, VOLUME 50 

in that and two smaller sets is summarized in Table XIV. The dis- 
tribution of diameter and H/D ratio is normal, but spread over a 
wide enough center in the case of the diameter to suspect that geo- 
graphical, altitudinal or both types of variation will be found. Neither 
of the two specimens over 70 mm. in diameter had locality data. 

Diameter in mm. 

44 47 50 53 56 59 62 65 68 71 
No. of specimens 1 2 7 16 17 16 16 7 1 2 

H/D ratio 

0.457 0.472 0.487 0.502 0.517 

No. of specimens 2 5 11 20 

0.532 0.547 0.562 0.577 0.592 

No. of specimens 19 15 6 4 3 

The obtusely rounded periphery, wide umbilicus with its internal 
groove, conspicuous parietal lamellar tooth, single lower palatal tooth 
and presence of weak malleations at once separate this species. /. 
fauna differs in lacking the parietal tooth and in being acutely angu- 
lated; most of the other species have the umbilicus nearly closed and 
the teeth are quite different. While the Ecuadorean species are read- 
ily separable, it is easy to see how they could have been derived from 
J. oreas simply by making minor alterations in shell structure. 

Isomeria kolbergi Miller, 1878. Figures 48c, 49b. 

Isomeria kolbergi Miller, 1878, Malak. Blatt., 25, pp. 167-168, pi. 8, fig. 2a, b 

—Valley of Pilaton, Ecuador (Boetzkes!); Cousin, 1887, Bull. Soc. Zool. 

France, 12, p. 257 — Yungas, Ecuador (Cousin!). 
Isomeria granulatissima Miller, 1878, Malak. Blatt., 25, pp. 168-169, pi. 8, 

fig. 3— Nanegal, Ecuador (Wolf!); Cousin, 1887, Bull. Soc. Zool. France, 

12, p. 255. 
Helix (Isomeria) faunus var. ritchieana Pilsbry, 1889, Man. Conch. (2), 5, 

p. 138, pi. 62, figs. 14-17— Pichincha, Northwest Ecuador. 
Helix (Isomeria) kolbergi (Miller), Pilsbry, 1889, Man. Conch. (2), 5, p. 148, 

pi. 43, figs. 46-47; Reibisch, 1896, Abhl. naturwiss. Gesell. Isis, Dresden, 

7, p. 56— Toachi Valley, Ecuador (Wolf!). 
Helix (Isomeria) granulatissima (Miller), Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 148-149, pi. 43, figs. 41-42; Reibisch, 1896, Abhl. naturwiss. Gesell. 

Isis, Dresden, 7, p. 56 — Cayandelet, Western Mts., Ecuador (Wolf!). 
Pleurodonte (Isomeria) kolbergi Miller, Pilsbry, 1894, Man. Conch. (2), 9, 

p. 94. 
Pleurodonte (Isomeria) granulatissima Miller, Pilsbry, 1894, loc. cit. 
Pleurodonte (Isomeria) faunus var. ritchieana (Pilsbry), 1894, loc. cit. 



SOLEM: NEOTROPICAL LAND SNAILS 173 

Helix (Isomeria) oreas Germain, 1907 (not Koch, 1844), Bull. Mus. Nat. hist, 
nat., Paris, 13, p. 53 (partly); Germain, 1910, Miss. Arc. de Meridien 
equatorial, 9 (3), pp. C12-C14 (partly). 

Range. — Upper Rio Esmereldas drainage; Central Ecuador from 
Ibarra to Cayandeled; Amazonian drainage from Rio Quijos to upper 
Rio Pastaza. 

Material.— Ecuador (CNHM 40643): Val de Pilat6n (CNHM 
100094, ANSP 82701); Los Puentes, Val de Pilatdn (CM 62.2587, 
ANSP 61696, type of ritchieana, ANSP 82700, CNHM 40634, 
CNHM 117850); Napo (CNHM 86683, CNHM 117848, CNHM 
117849, Jackson 5297); Mera (CNHM 86695, Jackson 5517); "Al- 
ciagy" (CNHM 40635); Nanegal (USNM 307680, Paris— as oreas, 
ANSP); Topo (ANSP 186857, Jackson 7433); Puyo, 5,000-6,000 feet 
elevation (ANSP 170722, Jackson 6226); Gualea (MCZ 76516); Mt. 
Chimborazo (MCZ 87566); Cerro de Loma (Paris — as oreas); Milpe 
(Jackson 4817) ; Mindo (Jackson 4723) ; Santo Domingo de los Colo- 
rados (Jackson 9744); Ibarra (Jackson 9740); Nachiyacu between 
Baeza and Archidona (Jackson 4709); "Quito" (USNM 316048- 
316050, USNM 318223). 

Diagnosis. — Umbilicus slightly to moderately open; basal lip with 
0-2 low swellings or nodules; lower palatal lip with one conical, mod- 
erately prominent tooth situated on lip; upper palatal lip white, 
rarely with an indistinct swelling or small tooth; periphery acutely 
to obtusely carinated, usually acutely; surface with very fine radial 
sculpture, lightly to moderately malleated near the periphery; pari- 
etal callus with thick, raised edge; color liver brown to reddish brown, 
or with greenish-yellow mottlings; lip white. Diameter 41.5-63.3 mm. 
(mean 51.1 mm.), H/D ratio 0.445-0.572 (mean 0.499). 

Remarks.- — Pilsbry apparently had not seen any specimens of kol- 
bergi when he described ritchieana, and would have been misled by 
Miller's description. /. kolbergi was described as having the last one- 
third whorl descending, gradually at first, then more rapidly. Only 
a very few specimens show this feature, most of them having a sud- 
denly and sharply deflected aperture as is normal in Isomeria. 

I. kolbergi is usually easily separated from I. jacksoni by its more 
widely open umbilicus and larger size. Form granulatissima differs 
only in having a distinct upper palatal tooth. Miller's cited differ- 
ences of a "viel flachere Gestalt, das Fehlen der Rippen, der weitere 
Nabel" failing to hold when numerous specimens are examined. It is 
a rare mutant, being found in two of ten shells from Puyo, Ecuador 
(Jackson 6226) and one of three from Nachiyacu (Jackson 4709), but 






174 FIELDIANA: ZOOLOGY, VOLUME 50 

did not occur in the large series of 37 specimens from Mera (Jackson 
5517). Size variation is summarized in Table XIV. 

The distribution is approximately the same as I. cymatodes, except 
for the fact that kolbergi extends further north and south than the 
recorded localities for I. cymatodes. Differences from cymatodes are 
fully covered in the discussion of the latter (p. 182). 

Distribution of the diameters is normal, but there is a distinct 
bimodality in the obesity index. 







Diameter in mm. 








43 46 


49 


52 55 


58 61 64 


No. 


of specimens 


7 12 


18 


38 20 


111 






H/D ratio 










0.452 


0.467 


0.482 


0.497 0.512 


No. 


of specimens 


7 


17 


17 


16 11 






0.527 


0.542 


0.557 


0.572 


No. 


of specimens 


23 


4 


2 


1 



The set from Puyo contains one of the high form and nine of the 
compressed variety; the large set from Mera (37 examples) has mostly 
the compressed variety. Since these two sets contained more than 
half of the available material, they easily could account for the bi- 
modal distribution. Unfortunately, no other set contained more than 
three examples. Thus there is no data on the variation in material 
from other localities. 

Possibly I. fauna (see p. 194) is a synonym. Until the Bogota area 
can be revisited, however, it seems best tentatively to keep them 
distinct. 

Isomeria triodonta (d'Orbigny, 1835). Figures 48d, 49c. 

Helix triodonta d'Orbigny, 1835, Guerin's Mag. de Zool., 1835, Class V, no. 61, 
p. 3 — Guayaquil, Ecuador; d'Orbigny, 1837, Voy. Amer. Merid., Moll., 
pp. 234-235, pi. 24, figs. 1-3 (plate issued in 1836)— Puna, Guayaquil, 
Ecuador; Pfeiffer, 1848, Monog. helic. viv., 1, p. 401; Reeve, 1854, Conch. 
Icon., Helix, pi. 208, fig. 1473; Pfeiffer, 1859, Monog. helic. viv., 4, p. 309. 

Helix atrata Reeve, 1852 (May), Conch. Icon., Helix, pi. 99, fig. 549 — Punto- 
phaya, Ecuador (Bourcier!). 

Isomeria triodonta (d'Orbigny), Miller, 1878, Malak. Blatt., 25, p. 170; Cousin, 
1887, Bull. Soc. Zool. France, 12, p. 258. 

Isomeria mauritii (sic) Jousseaume, 1887, Bull. Soc. Zool. France, 12, pp. 180- 
181 — New name for Helix atrata Reeve, 1852, not Helix atrata Pfeiffer, 
1854. 

Isomeria mauricei Cousin, 1887, Bull. Soc. Zool. France, 12, p. 256 — Emenda- 
tion of mauritii Jousseaume, 1887. 



SOLEM: NEOTROPICAL LAND SNAILS 175 

Helix (Isomeria) mauritii (Jousseaume), Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 145-146, pi. 44, fig. 7. 
Helix (Isomeria) triodonta d'Orbigny, Pilsbry 1889, loc. cit. (2), 5. p. 152, pi. 47, 

figs. 33-35. 
Helix (Isomeria) atrata var. Kobelt, 1893, Syst. Conch. Cab., I (12), 4, p. 631, 

pi. 181, figs. 3-6 (plate issued in 1886). 
Pleurodonte (Isomeria) mauritii (Jousseaume), Pilsbry, 1894, Man. Conch. (2) 

9, p. 94. 

Pleurodonte (Isomeria) triodonta (d'Orbigny), Pilsbry, 1894, loc. cit. (2), 9, 
p. 94. 

Range.— Unknown, since the only reported locality, Puna Island 
near Guayaquil, is merely the place where the type was purchased. 

Material.— Ecuador (CNHM 40641, CNHM 40650, CNHM 
100093, CNHM 132556, ANSP 64441, ANSP 78357, USNM 57282, 
USNM 307656, USNM 316052, Edinburgh, Zurich): Guayaquil 
(USNM 307492 ex Deyrolle). 

Diagnosis. — Basal lip with two close-set teeth near umbilicus, 
occasionally fused; lower palatal lip with prominent, white- tipped 
conical tooth; upper palatal lip with weak to usually prominent white- 
tipped tooth placed on or just above periphery; umbilicus usually 
with a slight lateral crack, occasionally imperforate; surface finely 
rib-striated, often heavily malleated on later whorls; parietal callus 
very thin, rarely with a raised white lip edge; periphery right to ob- 
tusely angled, occasionally protruding; color liver-brown, lip mainly 
brown, often with basal and part of upper palatal portions white. 
Diameter 39.2-51.8 mm. (mean 44.9 mm.), H/D ratio 0.481-0.667 
(mean 0.547). 

Remarks.- — Most collections have two forms separated, the smaller 
one called triodonta and the larger atrata. Available material does 
show a bimodal distribution of the diameter, but the importance of 
the difference cannot be assessed in the absence of localized collec- 
tions. The total range is no larger than that found in other species 
of Labyrinthus and Isomeria and easily could reflect populations from 

Diameter in mm. 

40 42 44 46 48 50 52 
No. of specimens 8 8 9 4 5 8 2 

H/D ratio 

0.490 0.510 0.530 0.550 0.570 
No. of specimens 2 8 9 9 11 

0.590 0.610 0.630 0.650 0.670 
No. of specimens 2 2 1 



176 FIELDIANA: ZOOLOGY, VOLUME 50 

dry and wet areas. There is no similar, bimodal distribution of the 
obesity index. In large and small sized populations of such species as 
Labyrinthus otis orthorhinus, there is no significant variation in H/D 
ratio. 

Neither of the two recorded localities can be considered reliable. 
Reeve's citation (loc. cit.) of "Puntophaya" is the type locality of 
Helix atrata Pfeiffer, 1854 (= Isomeriajacksoni Solem, 1966, see p. 178) , 
not Reeve, 1852 and probably has no reference to the mislabeled I. 
triodonta figured by Reeve. The type of triodonta was purchased by 
a ship's surgeon at Puna, Ecuador from a native who was wearing it 
as a single ornament suspended on a thong around his neck. The fact 
that it was worn as a single ornament suggests that it was a valued 
item obtained in trade rather than an object easily picked up locally. 
Similarly, the single specimen from "Guayaquil" (USNM 307492 
ex Deyrolle) probably had the locality added by Deyrolle on the 
basis of the type locality. 

There is some variation in the degree of carination and the extent 
to which malleations appear on the whorls. It seems obvious that 
the museum specimens have come from several populations. Some- 
times I. triodonta and I. aequatoria are confused. The latter has a 
smoothly closed umbilicus, no malleations, is smaller, and the upper 
palatal tooth is only a slight triangular projection; I. triodonta has 
the umbilicus slightly open or sealed by a secondary callus, is mal- 
leated on the later whorls, is larger, and has a lamellar upper palatal 
tooth. 

Isomeria stoltzmanni (Lubomirski, 1879). Figure 50a-e. 

Helix (Isomeria) stoltzmanni Lubomirski, 1879, Proc. Zool. Soc. London, 1879, 

p. 720, pi. 55, figs. 4-6 — Montana de Palto, near Tambillo, District of 

Chota, Peru (Stoltzmann!). 
Helix (Isomeria) stoltzmanni Lubomirski, Pilsbry, 1889, Man. Conch. (2), 5, 

p. 150, pi. 57, figs. 28-30. 
Pleurodonte (Isomeria) stoltzmanni (Lubomirski), Pilsbry, 1894, Man. Conch. 

(2), 9, p. 94. 

Range. — Known only from the type locality. 

Material. — Peru: CAJAMARCA — Montana de Palto, near Tam- 
billo, District Chota, Peru (Warsaw, holotype and paratype). 

Diagnosis. — The basal lip with 0-2 slight swellings near umbilicus; 
lower palatal lip with a very small conical tooth; upper palatal lip 
sinuated and somewhat thickened; umbilicus only slightly covered 
by basal and parietal lips; periphery nearly right angled; parietal 



SOLEM: NEOTROPICAL LAND SNAILS 



177 




Fig. 50. Isomeria stoltzmanni, Montana de Palto, near Tambillo, District 
Chota, Peru. Polska Akademia Nauk. Holotype. a, base; b, top; c, side; d, aper- 
ture of holotype; e, aperture of paratype. Scale lines equal 10 mm. 



callus with very heavy raised edge; surface with strong radial growth 
striae and grooves, but no trace of malleations; lip white on inner 
margins, slightly brown tinted on outer. Diameter 39-40 mm., H/D 
ratio 0.487-0.495, umbilical opening contained 12-14 times in the 
diameter. 

Remarks. — Apparently the nearest relative is I. kolbergi from 
Ecuador. J. stoltzmanni is a smaller, heavier shell, completely lacks 
malleations on the body whorl, has the palatal tooth much smaller 



178 FIELDIANA: ZOOLOGY, VOLUME 50 

and part of the lip is tinted brown. I. kolbergi may be only subspe- 
cifically separable, but in the absence of material from intermediate 
areas, no judgment can be made. 

The exact location of the type locality is uncertain. The Cerro 
de Palto is not in Chota District and is quite far from the two towns 
of Tambillo in Cajamarca, both of which are near Chota District but 
not within the present boundaries. 

Through the kind cooperation of Dr. A. Riedel of the Polska Aka- 
demia Nauk it was possible to examine the type and one paratype. 
The original figures were rather distorted and the type is refigured 
and redescribed. A new description of the type follows: 

Shell of average size, carinated, with slightly more than A.% 
whorls. Coiling of early whorls normal, last half of body whorl com- 
pressed laterally with reduced carination. Spire rather strongly ele- 
vated, slightly rounded above, H/D ratio 0.487. Apex with widely 
spaced radial growth lines, becoming finer and very crowded on spire. 
Surface of lower spire and body whorl with prominent granulations 
that are arranged in linear series on constricted portion of body whorl 
and are greatly reduced in size on base of shell. Periphery acutely 
angulated, nearly right angled, slightly protruded. Color greenish- 
yellow brown, lighter behind lip. Upper palatal lip and parietal callus 
white, lower palatal and basal lips with brownish tints on outer edge. 
Umbilicus narrowly open, contained 14 times in the diameter, with 
columellar groove clearly visible. Aperture ovate, very strongly de- 
flected, inclined about 75° from the shell axis, descending abruptly 
with deep, narrow posterior indention. Parietal wall without den- 
tition, but with a rather broad, raised callus, narrower in center, 
edges wider and elevated at upper corner. Basal lip strongly re- 
flected, thickened and elevated internally; lower palatal lip thickened 
and reflected with low conical knob surmounting lip and trace of pe- 
ripheral groove at upper margin; upper palatal lip somewhat sinuated, 
thickened, but less broadly reflected. Height of holotype 19.0 mm., 
diameter 39.0 mm. 

The paratype differs in having a straight raised edge to the pari- 
etal callus, a much more fully developed lower palatal tooth and two 
faint rounded bumps on the basal lip near the umbilicus (fig. 50e). 

Isomeria jacksoni new name. Figures 51a, 52a. 

Helix atrata Pfeiffer, 1854 (not Reeve, May 1852), Proc. Zool. Soc. London, 
1852, p. 153— Puntophaya, Ecuador (Bourcier!); Pfeiffer, 1853, Monog. 
helic. viv., 3, p. 258; Pfeiffer, 1854, Syst. Conch. Cab., I (12), 3, p. 366, 



SOLEM: NEOTROPICAL LAND SNAILS 179 

pi. 139, figs. 1-2 (plate issued in 1852); Hidalgo, 1870, Jour, de Conch., 
18, p. 31 — Macas and Napo, Ecuador; Hidalgo, 1870, Moluscos del Viaje 
al Pacifico, pp. 12-13; Pfeiffer, 1876, Monog. helic. viv., 7, p. 464; von 
Martens, 1885, Conch. Mitteil., 2 (5-6), p. 156 — Rio del Ciuto at Pichin- 
cha, Ecuador at 1,300-1,400 meters elevation (Stiibel!). 

Isomeria atrata (Pfeiffer, not Reeve, 1852), Miller, 1878, Malak. Blatt., 25, 
p. 167; Cousin, 1887, Bull. Soc. Zool. France, 12, p. 254— San Domingo, 
trail from Aloag to Chones, Ecuador (Cousin!). 

Helix (Isomeria) atrata Pfeiffer (not Reeve, 1852), Pilsbry, 1889, Man. Conch. 
(2), 5, pp. 144-145, pi. 44, figs. 3-4. 

Pleurodonte (Isomeria) atrata (Pfeiffer) (not Reeve, 1852), Pilsbry, 1894, Man. 
Conch. (2), 9, p. 94. 

Range. — Upper Esmereldas and Amazonian drainages in Central 
Ecuador. 

Material— Ecuador: "Andes of Ecuador" (USNM 516773); near 
Nanegal (ANSP); Mera (CNHM 85385, Jackson 9364); Topo (Jack- 
son 10915); Puyo (Jackson 6820); Sigchos (Jackson 9728); Ibarra 
(Jackson 9678). 

Diagnosis. — Basal lip with single low swelling; lower palatal lip 
with small conical tooth; umbilicus slightly open; periphery obtusely 
carinated; surface with very fine growth striae and granulations but 
no malleations; parietal callus with thick raised edge; color dark red- 
dish-brown or with many scattered, irregular greenish-yellow macu- 
lations. Diameter 32.2-45.4 mm. (mean 40.0 mm.), H/D ratio 
0.468-0.553 (mean 0.517). 

Remarks. — Most authors have realized that the Helix atrata of 
Reeve and Pfeiffer were distinct species, but no substitute has been 
proposed for Pfeiffer's homonym. Great pleasure is taken in dedi- 
cating this species to Ralph Jackson of Cambridge, Maryland, whose 
unrivaled collection of South American non-marine mollusks has 
made much of this study possible and in token recognition of his 
great help to many malacologists. 

The possibility exists that this is a dwarf race of /. kolbergi, per- 
haps equivalent to the dwarf form of L. raimondii. The few known 
specimens, however, are easily separable from specimens of /. kol- 
bergi taken at the same locality by the more covered umbilicus, 
thicker, more solid shell, much smaller size and slightly fewer whorls. 
Until the ecology of the two is studied, I'd prefer to keep them as 
distinct species. The extent of the size difference can be appreciated 
by noting the comparison in Table XIV, between sets of kolbergi and 
jacksoni from the same locality. 



180 



FIELDIANA: ZOOLOGY, VOLUME 50 



The few specimens from scattered localities are almost all in the 
collection of Ralph Jackson. Variation is summarized in Table XIV. 
No data on elevations is available. 



Habc 
id 




Fig. 51. Shells of: a, Isomeric/, jacksoni, Mera, Ecuador, CNHM 85385; b, Iso- 
meria cymatodes, Puyo, Ecuador, CNHM 86692; c, Isomeria cymatodes form pari- 
etidentata, Val de Pilaton, Ecuador, CNHM 60801; d, Isomeria fordiana, Marmato, 
Colombia, ANSP 33133. Holotype. Scale lines equal 10 mm. 



Isomeria cymatodes (Pfeiffer, 1852). Figures 51b-c, 52b. 

Helix cymatodes Pfeiffer, 1852, Zeitschr. f. Malak., 9 (5), p. 92 — locality un- 
known; Pfeiffer, 1853, Monog. helic. viv., 3, p. 208 — Ecuador; Hidalgo, 
1870, Moluscos del Viaje al Pacifico, p. 11, pi. 2, figs. 1, 3 — Napo, Ecuador 
(Martinez!). 

Isomeria cymatodes (Pfeiffer), Miller, 1878, Malak. Blatt., 25, p. 169 — Nane- 
gal (Wolf!), Val de Pilaton (Boetzkes!), Ecuador; Cousin, 1887, Bull. Soc. 
Zool. France, 12, p. 255 — Los Puentes, Canton de Quito, Ecuador (Cousin!). 

Helix (Isomeria) cymatodes Pfeiffer, von Martens, 1885, Conch. Mitteil., 2 
(5-6), p. 156— Nanegal, Ecuador at 1,000-2,000 meters elevation (Stubel!); 
Pilsbry, 1889, Man. Conch. (2), 5, pp. 146-147, pi. 46, figs. 24-26. 

Isomeria parietidentata Miller, 1878, Malak. Blatt., 25, pp. 169-170 — Val de 
Pilaton, Ecuador (Boetzkes!); Miller, 1879, op. cit., n. f., 1, pi. 5, figs. 
3a-c; Cousin, 1887, Bull. Soc. Zool. France, 12, p. 258— trail from Aloag 
to Chones, Megia, Ecuador (Cousin!). 

Helix (Isomeria) parietidentata (Miller), Pilsbry, 1889, Man. Conch. (2), 5, 
pp. 147-148, pi. 61, figs. 11-13. 



SOLEM: NEOTROPICAL LAND SNAILS 



181 




Fig. 52. Apertures of: a, Isomeria jacksoni, Mera, Ecuador, CNHM 85385; 
b, Isomeria cymatodes, Puyo, Ecuador, CNHM 86692; c, Isomeria for diana, Mar- 
mato, Colombia, ANSP 33133. Holotype. Scale lines equal 10 mm. 



Pleurodonle (Isomeria) cymatodes (Pfeiffer), Pilsbry, 1894, Man. Conch. (2), 
9, p. 94. 

Pleurodonle (Isomeria) parietidentata (Miller), Pilsbry, 1894, Man. Conch. (2), 
9, p. 94. 

Helix (Isomeria) oreas Germain, 1907 (not Koch, 1844), Bull. Mus. Nat. 
hist, nat., Paris, 13, p. 53 — Nanegal, Horongo, Ecuador (partly); Ger- 
main, 1910, Miss. Arc de Meridien equatorial, 9 (3), pp. C12-C14 — 
partly. 

Range. — Upper Napo and Pastaza Rivers on the Amazonian 
slopes and the upper Rio Esmereldas basin on the Pacific slopes at 
3,900-7,800 feet elevation. 

Material— Ecuador (Zurich, Edinburgh, ANSP 33136): "Quito" 
(Zurich, USNM 316051, USNM 317440, ANSP 30643); Nanegal 
(CNHM 102414, USNM 307443, ANSP); Mera (CNHM 86693, 
Jackson 10893, Jackson 5521); Napo (CNHM 86694, CNHM 117856, 



182 FIELDIANA: ZOOLOGY, VOLUME 50 

Jackson 5299); Puyo (CNHM 86692, ANSP 170729, Jackson 9337); 
San Nicholas (CNHM 40639, ANSP 60197); Val de Pilat6n (CM 
62.2585, CNHM 60801) ; Topo (Jackson 8821) ; Sigchos, west of Lata- 
cunga (Jackson 9730). 

Diagnosis.— Basal lip with 0-2 inconspicuous bumps; parietal wall 
with small lamellar to conical denticle; lower palatal lip with high 
conical tooth situated on lip; umbilicus nearly closed by extension of 
basal and parietal lips, closed rest of way by an accessory plate that 
is occasionally broken or missing; periphery obtusely angulated; sur- 
face with fine radial striae, very heavily malleated on lower whorls 
near periphery; color dark reddish-brown to light reddish-brown, oc- 
casionally speckled with greenish-yellow; lip white on basal margin, 
brownish tinted on part of upper palatal lip; parietal callus very thin 
with high, raised edge. Diameter 39.9-56.2 mm. (mean 50.0 mm.), 
H/D ratio 0.464-0.581 (mean 0.502). 

Remarks. — Occasionally specimens with a very small parietal tooth 
can be confused with I. kolbergi. The latter lacks a parietal tooth, has 
a pure white lip, generally a moderately open umbilicus, more sharply 
carinated periphery, weaker malleations and 53^ to 5% whorls (rarely 
5). In contrast, I. cymatodes has a small to large parietal tooth, 
brown markings on the outer part of the upper palatal lip, generally 
a completely closed umbilicus, obtusely angulated periphery, heavy 
malleations and only 434 to 4^ whorls (rarely 5). The secondary 
closure of the umbilicus by formation of an accessory plate is unique 
and easily separates I. cymatodes from J. oreas. 

In the shell collection at the Museum National d'Histoire Natur- 
elle, Paris, cymatodes and kolbergi are completely confused and min- 
gled, with the Ecuador material reported by Germain as oreas being 
a mixture of the former two species. 

If only a few specimens are available for study, a division into 
cymatodes and parietidentata becomes feasible. As soon as series of 
specimens are examined, the separation becomes untenable. The dif- 
ferentiating characters of parietidentata are a more broadly expanded 
lip, shallower posterior gutter behind the lip, more sharply deflected 
aperture (see fig. 51c). The longer sets from Mera and Puyo contain 
intergrades and indicate that parietidentata is an individual variation. 

All reported localities are from the Upper Rio Esmereldas drain- 
age on the Pacific slopes or the Rio Napo and Rio Pastaza drainages 
on the Amazonian side. The only cited elevation record is 3,900- 
7,800 feet elevation near Nanegal. 



SOLEM: NEOTROPICAL LAND SNAILS 183 

Size and shape variation is not very large. The distribution of 
the diameter suggests that dwarfed populations exist, since the curve 
is obviously skewed. The distribution of the obesity suggests that 
an occasional individual is exceptionally elevated. The four smallest 
shells are a pair from Mera (Jackson 10893) and Sigchos (Jackson 
9730) from opposite sides of the Andes. One of the Sigchos examples 
is also the most elevated specimen, but the other small shells are 
normally elevated. 



Dial 


neter in mm. 


40 42 


44 


46 


48 


50 52 


54 56 


No. 


of specimens 


2 2 


5 


8 


14 


18 30 


13 3 




H/D ratio 


0.467 


0.482 




0.497 


0.512 


0.527 


No. 


of specimens 


9 


19 




26 


24 


12 




H/D ratio 


0.542 


0.557 




0.572 


0.587 




No. 


of specimens 


1 


3 







1 





Variation in several sets is summarized in Table XV. 
Isomeria fordiana (Pilsbry, 1889). Figures 51d, 52c. 

Helix (Isomeria) fordiana Pilsbry, 1889, Man. Conch. (2), 5, pp. 141-142, 

pi. 62, figs. 18-21 — Marmato, Colombia. 
Pleurodonte (Isomeria) fordiana (Pilsbry), Pilsbry, 1894, Man. Conch. (2), 9, 

p. 94. 

Range. — One locality each in the Cauca and Magdalena drainages. 

Material— Colombia: CALD AS— Marmato (ANSP 33133, types) ; 
NORTE DE SANTANDER— ?Ocana (Zurich ex Wallis 1875). 

Diagnosis. — Basal lip with broad, low knob; lower palatal lip with 
small conical white- tipped tooth; umbilicus with barely open crack; 
periphery nearly right angled; parietal callus thin with raised edge; 
lip broad, brown inside, white on edge, strongly indented behind; 
surface with faint granulations and radial growth lines, but no mal- 
leations. Diameter 39.5-42.4 mm., H/D ratio 0.488-0.492. 

Remarks. — The umbilical closing is as in /. cymatodes, but the 
lack of a parietal tooth and absence of malleations on the body whorl 
at once separate the two species. J. fauna differs in having mallea- 
tions, a distinctly open umbilicus, right-angled periphery and in be- 
ing larger. 

Isomeria scalena (Martens, 1881). Figures 53c-e, 54c. 

Helix (Isomeria) scalena Martens, 1881, Conch. Mitteil., 2 (5-6), pp. 156, 170- 
172, pi. 31, figs. 1-3— Cerro Pelado, La Plata, Colombia at 2,300 meters 
elevation (Stiibel!). 



184 FIELDIANA: ZOOLOGY, VOLUME 50 

Helix (Isomeria) scalena Martens, Pilsbry, 1889, Man. Conch. (2), 5, pp. 143- 

144, pi. 61, figs. 1-3. 
Pleurodonle (Isomeria) scalena (Martens), Pilsbry, 1894, Man. Conch. (2), 9, 

p. 94. 

Range. — La Plata drainage of Huila, Colombia at 7,550-7,875 feet 
elevation. 

Material. — Colombia: HUILA — Rio Paez Valley, 2,400 meters ele- 
vation (USNM 251175); Hacienda Medersenberg, La Plata (SMF 
172173, CNHM 133152 E. Kohldorfs!). 

Diagnosis. —Aperture without teeth although basal lip greatly 
thickened; umbilicus nearly covered by lip extensions, almost com- 
pletely closed by a secondary callus; periphery acutely angulated or 
right angled; surface with prominent rib-striae, weakly malleated 
near periphery; parietal callus with elevated edge. Diameter 43- 
55 mm. 

Remarks. — The larger size, nearly closed umbilicus and total ab- 
sence of dentition separate scalena from the other known species of 
Isomeria. Of the toothless species, basidens and neogranadensis are 
much smaller and have a very obtusely angulated periphery; meyeri 
is much smaller, has the umbilicus closed by the expansion of the 
basal and parietal lips, and the lip is yellowish; while anodonta has 
the umbilicus widely open, the surface smooth without trace of angu- 
lation and is dull brown. 

The five specimens (diameter 43-50.7 mm., mean 47.2 mm., H/D 
ratio 0.492-0.563, mean 0.518) from La Plata and the Rio Paez, a 
tributary of the Rio La Plata that drains the slopes of Cerro Pelado 
and forms the headwaters of the Rio Magdalena, are much smaller 
than the type (diameter 55 mm., H/D ratio 0.528). The umbilical 
callus of J. scalena is the same as in I. fordiana and /. cymatodes, but 
the former differs in having a lower palatal tooth, a basal knob, and 
the aperture much more sharply deflected. The latter is much more 
heavily malleated and with several denticles. 

All localities are part of the same drainage system and are only a 
few miles apart. The three shells from Hacienda Medersenberg are 
larger (diameter 48-50.7 mm.) than those from the Rio Paez (diam- 
eter 43-44.1 mm.). 

Isomeria aequatoriana (Hidalgo, 1867). Figures 53a, 54a-b, 55a-c. 

Helix aequatoriana Hidalgo, 1867, Jour, de Conchy., 15, pp. 307-308, pi. 8, 
fig. 2— Ecuador; Pfeiffer, 1868, Monog. helic. viv., 5, p. 500; Pfeiffer, 1876, 
Monog. helic. viv., 7, p. 361. 






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Fig. 53. Shells of: a, Isomeria aequatoriana, Topo, Ecuador, CNHM 86677; 
b, Isomeria globosa, Mera, Ecuador, CNHM 86700; c-e, Isomeria scalena, Rio Paez 
Valley, 2,400 meters elevation, Colombia, USNM 251175 (c, top; d, base; e, side); 
/, Isomeria fauna(l), Santa Fe de Bogota, Colombia. Zurich. Scale line equals 
10 mm. 



186 




Fig. 54. Apertures of: a-b, Isomeria aequatoriana, Topo, Ecuador, CNHM 
86677 (a, normal form; b, with extra palatal teeth); c, Isomeria scalena, Rio Paez 
Valley, 2,400 meters elevation, Colombia, USNM 251175; d, Isomeria fauna (1), 
Santa Fe de Bogota, Colombia. Zurich. Scale line equals 10 mm. 



187 



188 FIELDIANA: ZOOLOGY, VOLUME 50 

Isomeria aequatoriana (Hildalgo), Miller, 1878, Malak. Blatt., 25, p. 167; 

Cousin, 1887, Bull. Soc. Zool. France, 12, p. 254. 
Helix (Isomeria) aequatoriana Hidalgo, Pilsbry, 1889, Man. Conch. (2), 5, 

pp. 142-143, pi. 47, fig. 39. 
Pleurodonte (Isomeria) aequatoriana (Hidalgo), Pilsbry, 1894, Man. Conch. 

(2), 9, p. 94. 
Helix (Isomeria) wolfi Reibisch, 1896, Abhl. naturwiss. Gesell. Isis., Dresden, 

7, pp. 56-57 — Machai (=Macas), Valley of the Rio Pastaza, Ecuador at 

4,900 feet elevation (Wolf!). 

Range. — Amazonian slopes of Ecuador from Rio Napo south to 
upper Paute River. Reported from 3,900-4,900 feet elevation. 

Material. -Ecuador (USNM 316053, ANSP 45556, ANSP 63586, 
CNHM 40637, CNHM 102430) : Rio Pastaza at 1,000 meters eleva- 
tion (CNHM 117852, CNHM 117853, CNHM 117855); Napo 
(CNHM 86682, Jackson 5448, CNHM 117851); Mera (CNHM 
86697, ANSP 175412, MCZ 195872, Jackson 6994); Topo (CNHM 
86677, Jackson 7435, CNHM 117854, MCZ 193302, MCZ 193310); 
Mendez, Upper Paute Valley (USNM 426539, CNHM 71046); Chi- 
quaza (ANSP) ; Oriente Prov. (USNM 628793) ; Abitagua, Pastaza 
Valley (Jackson 5718); 30 miles east of Banos (MCZ 96928); Loreto 
at 550 meters (SMF 156312); Puyo (Jackson 6227, MCZ 195875); 
Nachiyacu (MCZ 139960). 

Diagnosis. — Lower palatal lip with conical white tooth; upper pal- 
atal lip rarely with one or two small denticles or swellings; umbilicus 
usually completely closed by extension of lips, but occasionally with 
a moderate to wide lateral crack; periphery usually obtusely angu- 
lated; surface with very fine radial striae and granulations, but no 
malleations; lip brown tinted; parietal callus thin; lip broadly and 
slightly elevated ; color light liver-brown, usually with numerous fine 
yellowish flecks. Diameter 43.6-71 mm. (mean 54.1 mm.), H/D 
ratio 0.441-0.569 (mean 0.509). 

Remarks. — The usually closed umbilicus, lack of any malleations 
or a parietal tooth, presence of only a lower palatal tooth (occasion- 
ally one or two accessory palatal denticles) and brown lip easily 
identify this species. No authentic material of the unfigured wolfi 
(diameter 52-57 mm.) was examined, but material from the Rio Pas- 
taza was unquestionably aequatoriana and no hesitation is felt in 
synonymizing the two. The original description of wolfi is translated 
below for convenient reference: 

Shell almost lenticular, thick, obtusely keeled, with covered umbilicus. Whorls 
convex, five in number. Sutures fairly shallow near apex, becoming progres- 
sively deeper toward aperture so that whorls become more convex. Last 




Fig. 55. Type specimen of Isomeria aequatoriana. a top; b, base; c, side. 
Ecuador. Madrid. Holotype. 



189 



190 FIELDIANA: ZOOLOGY, VOLUME 50 

whorl deflected for about 5 mm. suddenly before aperture. Umbilical callus 
area impressed, convexity of whorls gradually increasing from upper edge of 
aperture to base. Upper surface finely grooved. Both surfaces with fine gran- 
ulations and wrinkles, which appear white from erosion. Aperture very 
oblique, proportion of breadth to length about 2:3. Lip slightly reflected 
above, more laterally and strongly basally, completely covering umbilicus. 
Upper and outer lip edges evenly curved, but sinuated basally. Medial por- 
tion bent a little upward, rest almost straight. Inner edge of palatal lip with 
white-tipped conical tooth. Some specimens with one or two small teeth 
placed above this tooth. Lip yellow brown, lighter near umbilical callus, 
which is almost white. Shell brown in fresh specimens, liver colored in dead 
examples. Parietal wall with thin, shining callus joining ends of the lips. 
Measurements — diameter 52-57 mm., height 21-23 mm. 

This is an excellent description of aequatoriana. 

The recorded localities are all from the Upper Amazonian basin 
from the Rio Napo south to the upper Paute River. It is not known 
how far into the lowlands it extends, the recorded elevations being 
1,800-4,900 feet. 

Size variation is rather extensive, the distribution of the diameter 
being strongly affected by the set from Mendez (USNM 426539, 
CNHM 71046) which contained 11 of the 14 specimens with a diam- 
eter of less than 49.5 mm. Other sets from Mera and Puyo averaged 
much larger (see Table XV), although no material reached the size 
of the type specimen (71 mm.) . Variation in the H/D ratio, as usual, 
was much less striking. 



Diameter in mm. 


45 48 


51 


54 


57 


60 63 


66 69 


No. of specimens 


6 8 


11 


20 


18 


6 


3 1 


H/D ratio 
No. of specimens 

H/D ratio 
No. of specimens 


0.447 

2 
0.522 

22 


0.462 

2 
0.537 

8 




0.477 

7 
0.552 

2 


0.492 

11 
0.567 

1 


0.507 
17 



During a study trip to Madrid, sponsored by the National Science 
Foundation and Field Museum of Natural History, the probable 
type of Helix aequatoriana was located and photographed (fig. 55). 

It is quite possible that the unrecognizable /. calomorpha (Jonas, 
1839) is J. aequatoriana. The size of the former (diameter 62 mm.) 
and its general appearance are rather similar, but it seems best to 
consider calomorpha a nomen dubium (see p. 139). 

Isomeria globosa (Broderip, 1832). Figure 56a-b. 

Carocolla globosa Broderip, 1832, Proc. Zool. Soc. London, 1832, p. 30 — woods 
on Tumaco Id., West Colombia. 



SOLEM: NEOTROPICAL LAND SNAILS 191 

Helix subcaslanea Pfeiffer, 1842, Symbolae hist, heliceorum, 2, p. 103 — New 
name for Carocolla globosa Broderip, 1832, not Helix globosa Sowerby, 1818, 
an unnecessary proposal; Pfeiffer, 1848, Monog. helic. viv., I, p. 401; 
Reeve, 1852, Conch. Icon., Helix, pi. 99, fig. 543. 

Isomeria subcastanea (Pfeiffer), Miller, 1878, Malak. Blatt., 25, pp. 170-171 — 
Val de Pilat6n, Pisagua, Milagro, Ecuador at 500-1,500 meters elevation 
(Boetzkes!); Miller, 1879, op. cit., n.f., 1, pp. 117-118— forests of Rio 
Esmereldas, Prov. Esmereldas, Ecuador at 0-300 feet elevation (Wolf!); 
Cousin, 1887, Bull. Soc. Zool. France, 12, p. 258— trail from Aloag to 
Chones, Canton Megia, Ecuador (Cousin!); Gude, 1900, Jour, of Malac. 
7 (6), pp. 144-146, figs. 3-4— Paramba, Ecuador at 3,500 feet elevation 
(Rosenberg!). 

Helix (Isomeria) subcastanea Pfeiffer, Pilsbry, 1889, Man. Conch. (2), 5, 
p. 157, pi. 44, figs. 8-10; Kobelt, 1894, Syst. Conch. Cab., I (12), 4, pp. 
630-631, pi. 181, figs. 1-2; Reibisch, 1896, Abhl. naturwiss. Gesell. Isis., 
Dresden, 7, p. 56 — Bulubulu Mt. and Manabi, Ecuador (Wolf!). 

Pleurodonte (Labyrinthus) subcastanea (Pfeiffer), Pilsbry, 1894, Man. Conch. 
(2), 9, p. 94. 

Isomeria subcastanea var. kobeltiana Gude, 1900, Jour, of Malac, 7 (6), pp. 
144-146, figs. 1-2— Ecuador. 

Helix (Isomeria) equestrata Germain, 1907 (not Moricand, 1858), Bull. Mus. 
national hist, nat., Paris, 13, p. 53 — Albanfn, Rio Jubones Valley and 
Cerro de Castello, Mindo, Ecuador (Rivet!); Germain, 1910, Miss. Arc 
de Meridien Equatorial, 9 (3), pp. C14-C15, pi. 2, figs. 8-10. 

Range. — Pacific lowlands from Tumaco Island, Narifio, Colombia 
south to Rio Jubones basin, up to at least 3,500 feet elevation at 
Paramba and Huigra, probably 7,500 feet at San Jose de Minas and 
Ibarra. Also reported from Mera, Topo and Napo on the Atlantic 
slopes. 

Material— Ecuador (CNHM 132557, Zurich, Edinburgh) : Mera 
(CNHM 86700, Jackson 7853); Napo (CNHM 117857); San Jose de 
Minas, Upper Guayllabamba at 2,000-2,500 meters (ANSP); Pa- 
ramba (CNHM 40645, SMF 82574, Edinburgh); Ibarra (CNHM 
70909, Jackson 9737) ; 6 miles below Huigra (ANSP 157073, CNHM 
78830) ; between Manglaralto and Naute (USNM 517607) ; between 
Quevedo and Calceta, Manabi (USNM 534078); Val de Pilat6n 
(USNM 307397, ANSP 82702, CM 62.4041); Bucay, Pr. Guayas, 
1,000 feet elevation (ANSP 148445); Rio Macima, Rio Marone 
(SMF 15631); Chimbo (Edinburgh); Cerro Masvale, Prov. Guayas 
(USNM 534045); Milpe (Jackson 5103, ANSP); Sigchos (Jackson 
9729) ; Mindo (Jackson 5116) ; Santo Domingo de los Colorados (Jack- 
son 9743); Topo (Jackson 7434); lowlands of Guayas and Manabi 
(MCZ 139888). Colombia (ANSP 30645). NARINO— Rio Rosario, 
east of Tumaco (CNHM 133262). 






192 



FIELDIANA: ZOOLOGY, VOLUME 50 



Diagnosis. — Basal lip with a single broad ridge, rarely with two 
indistinct denticles; lower palatal lip with a large, crescentic lamella 
extending back into aperture and marked by a deep sulcus behind lip; 
rarely a small accessory palatal tooth located on periphery (fig. 56b) ; 





Fig. 56. Apertures of: a, Isomeria globosa, Mera, Ecuador, CNHM 86700; 
b, Isomeria globosa form kobeltiana, Huigra, Ecuador, CNHM 78830. Scale line 
equals 10 mm. 

umbilicus closed to partly open; periphery obtusely angulated with 
lighter color band, spire quite elevated; parietal callus varying from 
thin to with a broadly raised, thick edge; surface with granulations 
and fine to moderately prominent striae, rarely with malleations; lip 
white, rest of shell dark liver brown. Diameter 32-51.8 mm. (mean 
42.3 mm.), H/D ratio 0.472-0.591 (mean 0.527). 

Remarks. — Germain's excellent figures (loc. cit.) are unquestion- 
ably of globosa and not of equestrata. The specimen he illustrated 
seems to be intermediate between typical globosa and variety kobelti- 
ana. In typical globosa the umbilicus is narrowly to partly open, the 
parietal callus is very thin and without raised edges and the surface 
sculpture is much finer and without malleations. In form kobeltiana 
the umbilicus is closed, the parietal callus has a thick, broad raised 
edge and the surface sculpture is much stronger. 

The only specimens that matched the type description of kobelti- 
ana were from below Huigra, Ecuador (ANSP 157073, CNHM 
78830). Most of the other examples were intermediate between glo- 
bosa and kobeltiana. While the latter may eventually be given sub- 
specific status, present data suggests it is only an extreme variant. 

Earlier authors, utilizing Helix in an extremely broad sense, had 
considered that Carocolla globosa Broderip, 1832 was a homonym of 



SOLEM: NEOTROPICAL LAND SNAILS 193 

Helix globosa Sowerby, 1818. Under Article 59, Section (c) of the 
International Code of Zoological Nomenclature, they are not homo- 
nyms and we must return to Broderip's earlier name, rather than the 
familiar subcastanea. 

Isomeria globosa has a quite wide range at low to intermediate 
elevations on the Pacific slopes of Ecuador and has been reported 
from three locations in the upper Amazonian drainage. The southern 
limit is very uncertain, since practically no collections of mollusks 
are known from northern Peru and Ecuador below the Rio Jubones 
basin. Despite the wide geographic range, there is very little shell 
variation, much less than was seen in other species. Variation in one 
large set is summarized in Table XV. The distribution of the diam- 
eter was quite clumped with the largest a shell from "Guayaquil" 
and the two smallest coming from what is obviously a dwarfed pop- 
ulation in the isolated Cerro Masvale, Guayas Province. Variation 
in the H/D ratio was larger, but not unusual. 



Diameter in mm. 
No. of specimens 


33 35 
2 


37 



39 

7 


41 
22 


43 45 
33 9 


47 49 
2 


51 
1 


H/D ratio 
No. of specimens 


0.477 
3 


0.492 
3 




0.507 
16 


0.522 
17 


0.537 
20 




H/D ratio 
No. of specimens 


0.552 

8 


0.567 
5 




0.582 



0.597 
2 







The lower palatal lamella with its posterior indention is much 
larger than the tooth in any other species of Isomeria. When com- 
bined with the lighter zoned periphery, it at once identifies this 
species. Since globosa is the only lowland Isomeria, the greater devel- 
opment of the lower palatal tooth may reflect the need for protection 
from lowland predators. 

NOMINA DUBIA 
Isomeria calomorpha (Jonas, 1839) 

Helix calomorpha Jonas, 1839, Arch. f. Naturgesch., 1839, p. 341, pi. 10, figs. 

3-4 — Locality unknown; Pfeiffer, 1848, Monog. helic. viv., 1, pp. 315-316; 

Pfeiffer, 1876, Monog. helic. viv., 7, p. 361. 
Helix (Isomeria) calomorpha Jonas, Pilsbry, 1889, Man. Conch. (2), 5, p. 142, 

pi. 47, figs. 31-32. 
Pleurodonte (Isomeria) calomorpha (Jonas) Pilsbry, 1894, Man. Conch. (2), 

9, p. 94. 



194 FIELDIANA: ZOOLOGY, VOLUME 50 

Remarks. — The type of this unlegalized species is unknown and 
the original figures are obviously distorted. It is an unidentifiable 
name and can be considered a nomen dubium. Of the species of Iso- 
meria, the most probable identification is with I. aequatoriana (see 
p. 184), but nothing would be gained by synonymizing the two. Un- 
less the missing type of calomorpha is discovered, the name should 
be ignored. 

Isomeria fauna (Philippi, 1851). Figures 53f, 54d. 

Helix fauna Philippi, 1851, Zeits. f. Malak., 8 (2), pp. 29-30— Mts. near Santa 

Fe de Bogota, Colombia; Pfeiffer, 1853, Monog. helic. viv., 3, pp. 257-258; 

Pfeiffer, 1854, Syst. Conch. Cab., I (12), 3, p. 416, pi. 148, figs. 1-3 (plate 

issued in 1853). 
Helix (Isomeria) faunas Philippi, Pilsbry, 1889, Man. Conch. (2), 5, pp. 137- 

138, pi. 46, figs. 21-23. 
Pleurodonte (Isomeria) faunus (Philippi), Pilsbry, 1894, Man. Conch. (2), 9, 

p. 94. 

Range. — Known only from the type locality. 

Material. — Colombia: "Santa Fe de Bogota" (ZMA, Zurich, ex 
Hoffman, 1851). 

Diagnosis. — Basal lip with a low swelling; lower palatal lip with 
small conical tooth; umbilicus moderately open; periphery acutely 
angulated, protruded; surface with fine radial striae and granula- 
tions, lightly malleated near periphery; lip thin and white; color dark 
reddish-brown; parietal callus with strong but narrow raised edge. 
Diameter 47-57.9 mm. 

Remarks. — The status of this species is uncertain. The original 
figure is of a probably juvenile shell. The two specimens examined 
may be paratypes. They differ from kolbergi only in insignificant 
details, primarily in having the lower palatal tooth more lamellate, 
the malleations weaker and in being rather large. They could, how- 
ever, be mislabeled specimens of kolbergi, since they fall within the 
size range of that species. The type figure, however, shows a much 
more elevated shell with flatter-sided spire and thinner, straighter 
lips. The location of the type is unknown. Rather than prema- 
turely synonymize this, I have chosen to leave it as an unidentifi- 
able species. 

Isomeria equestrata (Moricand, 1858) 

Helix equestrata Moricand, 1858, Rev. Mag. Zool., 1858, pp. 449-450, pi. 13, 
fig. 1 — Moyobamba, Peru; Pfeiffer, 1868, Monog. helic. viv., 5, p. 315; 
Pfeiffer, 1876, Monog. helic. viv., 7, p. 361. 



SOLEM: NEOTROPICAL LAND SNAILS 195 

Helix (Isomeria) equestrata Moricand, Pilsbry, 1889, Man. Conch. (2), 5, 

p. 151, pi. 48, figs. 45-46. 
Pleurodonte (Labyrinthus) equestrata (Moricand), Pilsbry, 1894 (2), 9, p. 94. 

Diagnosis. — Basal lip without teeth; lower palatal lip with a broad 
conical tooth; periphery obtusely angulated (?); umbilicus slightly 
open; parietal callus very thin, without raised edge; surface with 
moderately prominent growth striae and grooves; lip white, some- 
what thickened. Diameter 36 mm. (from original description). 

Remarks. — The partly open umbilicus, obtusely angulated periph- 
ery and single palatal tooth identify this species. Conceivably, it 
could have been based on subadult individuals of /. meobambensis 
Pfeiffer. Only one specimen from Puca Tambo, Amazonas, Peru at 
5,100 feet elevation (Brit. Mus. 1929.6.11.3, R. W. Hendes!, 1-1926) 
could be this species. The lower palatal tooth is a small nodule with- 
out the upper lateral extension of /. meobambensis. It is 20.7 mm. 
high, diameter 41.6 mm., H/D ratio 0.498 with 4%+ whorls. Puca 
Tambo (77°17'W, 6°9'S) is not far from Moyobamba. The specimen 
could have been subadult. Without more material, I cannot decide 
whether equestrata is a valid species or a synonym of meobambensis. 



ZOOGEOGRAPHY 

DISTRIBUTION OF LABYRINTHUS 

Currently available collections extend the known range of Labry- 
rinthus from Sarapiqui, Heredia, Costa Rica (L. triplicatus) south to 
Hacienda Cadena, Dist. Marcapata, Dept. Cusco, Peru (L. diminu- 
tus). There are numerous records from Panama and the lowlands 
of Northern Colombia. Most species are known from the mountain- 
ous areas of Venezuela as far east as Caracas (L. plicatus), Colombia, 
Ecuador and much of Peru. South of Buenaventura, Valle de Cauca, 
Colombia, all except three records of Labyrinthus are from the At- 
lantic slopes of the mountains. In Ecuador there is one record of 
L. manueli and two records of L. raimondii from the Pacific drainage. 
No Labyrinthus has been found in Colombia between Victoria, Caldas 
and Monteredondo, Cundinamarca in Central Colombia and the 
Caqueta River, Putumayo in Southern Colombia. Quite possibly 
this is an artifact of collecting. Except for L. manueli (L. isodon 
group), all the Labyrinthus of southern Colombia, Peru and Brazil 
are members of the L. raimondii group. L. manueli has a rather wide 
range in Ecuador, while the raimondii series extends along the fringes 
of the Amazonian basin at low to medium elevations. Scattered Bra- 
zilian records from Rio Jurua, Rio Solimoes and Rio Tapajoz in Para 
only hint at the extent of Brazilian distribution. 

Collections of mollusks from the main Amazonian basin are prac- 
tically non-existent, hence the lack of current records has no distri- 
butional importance. 

Each of the well-defined species groups shows a separate geo- 
graphic pattern. The L. isodon complex (fig. 57) has the species with 
the simplest teeth in Costa Rica and the western tip of Panama 
(L. triplicatus and L. quadridentatus) then at lower elevations in 
coastal central Venezuela (L. tamsianus). More complex dentition is 
seen in L. leucodon from higher elevations in the coastal regions of 
central Venezuela and L. isodon from the southern end of the Sierra 
de Perija. There is an early (1853) unconfirmed record of L. leucodon 
from Tovar, MeYida, Venezuela. L. dunkeri and L. magdalenensis, 

196 




3 



197 



198 FIELDIANA: ZOOLOGY, VOLUME 50 

also from the Sierra de Perija, have quite specialized dentition. The 
remaining two species, L. vexans from Canasgordas and Frontino, 
Antioquia and L. manueli from Ecuador could be derived from L. 
isodon with a minimum of changes and show perfect union of the 
parietal lamella with the lip, compared with the less perfect junction 
in L. isodon. The species near the south and central portions of the 
range have the most complex dentition, with those on the distribu- 
tional fringes (Costa Rica and coastal Venezuela) having the least 
complicated dentition. 

L. otostomus, apparently from the Magdalena and Cauca basins, 
has complex dentition easily derived from the vexans-manueli type, 
as does the very large L. aenigmus from Frontino, Antioquia. It is 
less certain that L. clappi from the Sierra Nevada de Santa Marta 
should be considered a similar development, but the general similarity 
to L. aenigmus has led to its placement in that group. Equally 
difficult is to determine the possible affinities of L. sieversi, also from 
the Sierra Nevada de Santa Marta. For convenience it has been 
grouped with the raimondii series, but it could be a separate deri- 
vation from the isodon complex. A very interesting problem is the 
question of why both species of Labyrinthus from the Sierra Nevada 
de Santa Marta should be imperforate, when only one of the other 
twenty-seven species has a closed umbilicus. With our present com- 
plete lack of ecological data, obviously no answer can be given. 

Except for the already mentioned L. sieversi, members of the 
raimondii series are confined to the Amazonian basin (fig. 58) . (L. 
ellipsostomus from "Santa Fe de Bogota" may be an exception, al- 
though there should be slight difference between the Upper Orinoco 
and Upper Amazonian basin faunas). Provided the species are 
correctly delineated above, individual forms can show a wide geo- 
graphic range, L. raimondii extending over a triangular area from the 
Upper Caqueta Drainage in Colombia south to Pucalpa, Loreto, Peru 
and east to the confluence of the Rio Tapaj6z and Amazon in Para, 
Brazil. Similarly, L. ellipsostomus may range from the Upper Orinoco 
basin south to the Rio Maranon, Rio Jurua and east to the Rio 
Solimoes. The probable derivatives of L. ellipsostomus (L. diminutus 
and L. pronus) and the other members of the raimondii series are only 
known from Amazonian Peru at elevations of a few hundred to 
7,000 feet. 

L. unciger is known from low to medium elevations from Central 
Panama south to Choco, Colombia just below the Panamanian bor- 
der near the Golfo de Uraba. L. creveauxianus has been reported 




a 



a 
n 



a 



1 



8 

C 



g 



199 



200 FIELDIANA: ZOOLOGY, VOLUME 50 

only from Frontino, Antioquia, Colombia, but could live at higher 
elevations in Dari£n, Panama as does a bulimulid, Sultana (Clathor- 
thalicus) ivallisi (Strebel, 1909) (data from Solem mss.). Several 
examples of L. subplanatus are known from the Pacific coast of Co- 
lombia as far south as Buenaventura, but no material of L. unciger 
has been taken in this region. 

The remaining complex, that of L. otis, contains two geograph- 
ically isolated species, L. marmatensis from the Cauca drainage and 
L. plicatus from central mountains of Northern Venezuela, and two 
with partly overlapping distributions (fig. 59) . L. marmatensis and 
L. plicatus present no problems but the distribution and relationships 
of L. otis and L. subplanatus are still uncertain. L. otis is divided into 
two subspecies, L. otis orthorhinus from just south of the Panamanian 
border north to El Valle, Code" Prov., and then reappearing in San 
Jose* and Puntarenas, Costa Rica, and L. otis otis from the Pacific 
coast of Choco as far south as Nuqui and then several localities around 
the Gulf of Uraba over to Cartagena and up the Magdalena valley as 
far as Barrancabermeja, Santander and Monteredondo, Cundina- 
marca. While no intergrades between otis and orthorhinus are known, 
the only fully consistent difference (presence of a deep supra-sutural 
groove on the body whorl of the nominate race, see fig. 31) is minor 
and subject to moderate variation. L. subplanatus is divided into 
three subspecies. Two of them, L. subplanatus erectus and L. subpla- 
natus sipunculatus, range from Central Panama south to Buenaven- 
tura, Valle de Cauca and as far inland as Frontino, Antioquia. L. s. 
erectus has the more southern range with intergrades having been 
taken near Nuqui, Choco. The original record of L. s. erectus from 
"Bogota" is questionable, although not impossible. L. s. subplanatus 
is geographically isolated, having been taken in the Magdalena drain- 
age from near Puerto Santos, Santander, upstream as far as Victoria 
near the Caldas-Tolima boundary. Possibly old records from Ocana, 
Norte de Santander are correct. L. otis otis and L. subplanatus 
subplanatus have thus been collected in the same region, but not at 
the same locality. Similarly, L. otis orthorhinus and L. subplanatus 
sipunculatus have been collected from the same areas in Panama, 
but not at the same time by the same collector. Some specimens of 
L. s. subplanatus are very close to L. s. erectus, and little hesitation 
is felt in considering them subspecies. 

The two species of uncertain status, L. euclausus from Zaragoza 
(? Antioquia) and L. sharmani from Alejandria, Antioquia in the 



CO 

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CN 






o 

CO 




I 

o 
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S 



a 



a 

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a 

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a 



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201 



202 FIELDIANA: ZOOLOGY, VOLUME 50 

Cauca drainage system would not add any great extensions to the 
distributions outlined above. 

In very few cases are there reliable records of two species having 
been collected at the same locality. Early records such as "Ocana," 
"Chino," "Puerto Cabello," "Meobamba," "Bogota," etc. represent 
only the point of purchase by early collectors and can cover a great 
territory of collecting activity. Even modern collections from Cerro 
Campana, Panama, Acandi, Colombia, or Nuqui, Colombia made by 
different people over a period of years can easily have come from eco- 
logically diverse situations. The geographic name is no guarantee 
that the two species can be found living under the same ecological 
conditions in a particular patch of forest. H. B. Baker (1926, pp. 16- 
21) collected L. tamsianus and L. plicatus at different localities in 
Venezuela. Thompson (1957, pp. 5-7) reported L. plicatus and L. leu- 
codon umbrus from Rancho Grande, Aragua, Venezuela, but the speci- 
mens were collected by herpetologists in a series of visits and easily 
could have come from different ecological zones. There are two situ- 
ations where museum collections contain material of two or more 
species taken at the same locality by one collector during the same 
trip. L. magdalenensis and L. dunkeri were found by M. A. Carriker 
at Tierra Nueva, Sierra Negra, Magdalena, Colombia between 3,700 
and 5,000 feet elevation. No ecological data accompanied the shells, 
which were collected alive or just after death. L. leprieurii, L. pronus 
and L. tarapotoensis baeri were collected by G. Rozanski at Doma 
Santa Clara, 6°55'S, Ucayali Valley, Loreto, Peru. The shells were 
all dead, worn examples and could have come from river drift. 

In February 1959 I collected aestivating L. unciger and L. otis 
orthorhinus from under the same log in the restricted patch of forest 
behind the Club Campestre, El Valle, Code* Province, Panama. The 
species were moderately common in the forested area, but the aesti- 
vating specimens provided no data of possible ecological differences 
between the two species. Unfortunately, this is the only case where 
two species of Labyrinthus can be shown to be inhabiting the same 
local habitat. 

While there is no information about ecological relationships of 
members of different species groups inhabiting the same specific area, 
there are several possible cases where such a situation could be ex- 
pected to exist. In the Pacific areas of Costa Rica, it is quite possible 
that L. otis orthorhinus and L. quadridentatus may overlap in distri- 
bution; we do know that L. unciger and L. otis orthorhinus live to- 
gether in Panama; possibly L. leucodon and L. plicatus overlap in 






SOLEM: NEOTROPICAL LAND SNAILS 203 

parts of Venezuela; L. creveauxianus, L. aenigmus and L. vexans, rep- 
resenting three species groups, have been reported from Frontino; 
and L. manueli and L. raimondii are recorded from the same regions 
in Ecuador. The record cited above for museum material of two 
species from Tierra Nueva and three species from Domo Santa Clara 
are both examples of members of the same species group inhabiting 
the same area, and the variously overlapping distributions of L. otis 
and L. subplanatus fall into the same category. The Sierra Nevada 
de Santa Marta has both L. clappi and L. sieversi present, but up to 
now they have been taken at widely separated stations. Unquestion- 
ably, the forms delineated in the raimondii complex show overlapping 
distributions. 

Thus, the quite large, easily observable Labyrinthus offer good 
opportunities for investigating the ecological relationships of closely 
related species, as well as species that belong to different species groups 
and are inhabiting the same area. 

Altitudinal Zonation 

Available data on the altitudinal range is summarized in Figure 60. 
Many of the records are based on a single collection (designated by 
an "X") or for an estimate from the type locality (designated by an 
"E") . In making the latter guesses, I have utilized data from various 
ornithological gazetteers giving the probable altitudinal range covered 
by 19th century locality records. In view of the scanty data and the 
diverse ecological conditions prevailing over the range of Labyrinthus, 
the importance of altitudinal range is not great, and the meaning of 
the differences impossible to assess. The following few comments are 
intended only as a guide for possible investigations. 

From over 4,000 feet From under 600 feet 



L. TRIPLICATUS 


L. TRIPLICATUS 


L. SIEVERSI 


L. quadridentatus 


L. magdalenensis 


L. tamsianus 


L. dunkeri 


L. SIEVERSI 


L. tarapotoensis 


L. leprieurii 


L. PRONUS 


L. ellipsostomus 


L. vexans 


L. manueli 


L. aenigmus 


L. PRONUS 


L. clappi 


L. diminutus 


L. otostomus 


L. raimondii 


L. sharmani 


L. unciger 


L. creveauxianus 


L. OTIS 


L. OTIS 


L. subplanatus 


L. marmatensis 


L. plicatus 



Labyrinthus 



thousands 
of feet 
7-1 




20 22 23 25 26 27 



Fig. 60. Altitudinal range of Labyrinthus. The species are: 



1. 


L. triplicates 


16. 


L. raimondii 


2. 


L. q. quadridentatus 


17. 


L. aenigmus 


3. 


L. q. biolleyi 


18. 


L. clappi 


4. 


L. tamsianus 


19. 


L. otostomus bogotensis 


5. 


L. leucodon umbrus 


20. 


L. unciger 


6. 


L. magdalenensis 


21. 


L. creveauxianus 


7. 


L. dunkeri 


22. 


L. o. otis 


8. 


L. vexans 


23. 


L, o. orthorhinus 


9. 


L. manueli 


24. 


L. s. subplanatus 


10. 


L. sieversi 


25. 


L. s. erectus 


11. 


L. ellipsostomus 


26. 


L. s. sipunculatus 


12. 


L. diminutus 


27. 


L. plicatus 


13. 


L. pronus 


28. 


L. marmatensis 


14. 


L. leprieurii 


29. 


L. euclausus 


15. 


L. t. tarapotoensis 


30. 


L. sharmani 



"X" indicates only a single record; "E' 
early ornithological collections. 



an estimate based on evaluation of 



204 



SOLEM: NEOTROPICAL LAND SNAILS 205 

Of the thirty recognized species, four (L. isodon, L. bifurcatus, 
L. furcillatus and L. sp.) are not sufficiently localized to give any 
guess as to altitudinal range. Of the remaining twenty-six species, 
fourteen have been recorded from over 4,000 feet elevation and four- 
teen from less than 600 feet elevation. Four species (in capitals) 
occur on both lists. 

There are shorter lists of species known only from over 3,500 feet 
or from under 3,000 feet. 

From over 3,500 feet From under 3,000 feet 

L. leucodon umbrus* L. quadridentatus 

L. magdalenensis* L. tamsianus 

L. vexans* L. leprieurii* 

L. aenigmus* L. ellipsostomus* 

L. clappi L. manueli 

L. sharmani* L. unciger 

L. creveauxianus* L. subplanatus 

L. marmatensis L. euclausus* 

All those followed by an asterisk (*) are reported from only one ele- 
vation or exact locality. This applies to almost all of those recorded 
only from over 3,500 feet and to three of the eight recorded only from 
under 3,000 feet elevation. Even in the case of L. clappi, all recorded 
material was taken by Herbert H. Smith in 1900-1902 and there have 
been no subsequent collections. Hence the altitudinal range can 
hardly be considered well-defined. 

A number of species are known to have a considerable vertical 
range. Ranked in order from largest down, giving the recorded range 
in feet, they are: 

Recorded vertical range of Labyrinthus 

L. pronus — 6,445' L. plicatus — 3,600' 

L. dunkeri — 5,350' L. diminutus — 3,300' 

L. sieversi — 5,170' L. raimondii — 3,000' 

L. otis — 4,900' L. quadridentatus — 2,600' 

L. triplicatus — 4,850' L. unciger — 2,400' 

L. tarapotoensis — 4,025' L. subplanatus — 2,100' 

These figures clearly show that, in general, Labyrinthus is an inhabi- 
tant of lowlands or only moderately elevated areas. Nearly all of 
the species for which a number of modern collections are available 
have an altitudinal range of over 3,000 feet. While several species have 
only been collected at altitudes of over 3,500 feet, they are all based 
essentially on one collection. We thus have no idea whether they 
reach much higher or lower altitudes. Only seven of the thirty spe- 
cies have been reported from over 5,500 feet. This is in marked con- 



206 FIELDIANA: ZOOLOGY, VOLUME 50 

trast with Isomeria, which is generally found at much higher eleva- 
tions in the Andes, only reaching lowland situations on the Pacific 
slopes, where Labyrinthus is absent. 

Distribution of Isomeria 

The center of distribution for Isomeria is the area from the upper 
Rio Esmereldas basin of Ecuador across the Andes to the Napo and 
Pastaza drainages on the Amazonian slopes. A few species extend 
south to the Catamayo Valley and three species are known from Peru 
— I. meobambensis from "Moyobamba"; and J. anodonta from Prov. 
Jaen and I. stoltzmanni from Dist. Chota, both in Dept. Cajamarca. 
Only one species reaches the Pacific lowlands, I. globosa, which ranges 
from Tumaco Island, Narino, Colombia south to the Rio Jubones 
basin in southern Ecuador. In Colombia, most species are known 
from the Rio Cauca basin and Cordillera Central as far north as 
Angel6polis, Antioquia. Surprisingly, the only records for the Mag- 
dalena basin are from the headwaters of the Rio La Plata in Huila 
(I. scalena) ; Caldas, Tolima and Cundinamarca in the central region 
(I. continua and I. minuta); and the meaningless "Bogota" (7. basi- 
dens basidens, I. continua). Two species, I. oreas and I. continua, 
have been collected in the vicinity of Villavicencio, Dept. Meta, Co- 
lombia in the Upper Orinoco Basin. Records based on material in 
old collections for Frontino, Antioquia (I. oreas) and Ocana, Dept. 
Norte de Santander in the Sierra de Perija (I. continua, I. fordiana) 
require confirmation. Finally, there are the isolated records in the 
Sierra Nevada de Santa Marta (J. inexpectata, I. medemi). 

The amount of distributional data is surprisingly meager. The 
following species lack any authenticated locality — I. basidens basi- 
dens, I. neogranadensis, I. morula, I. meobambensis, I. meyeri and 
I. triodonta. Several other species are known only from the type col- 
lections, have not been found subsequently, and the exact locality 
where the type was collected is uncertain — I. aloagana, I. gealei, 
I. stoltzmanni and I. fordiana. The recently described I. anodonta, 
I. medemi, I. minuta and I. inexpectata are known only from the types 
and I. basidens gudeana, I. aequatoria and I. scalena have been re- 
ported only from localities that are within a few miles of each other. 
Thus, seventeen of the twenty-nine species and subspecies are based 
on material from essentially one locality; eleven of these do not have 
a restricted type locality; and thirteen are based on a single collection. 
Three of the remaining twelve species are Colombian: I. subelliptica 
from Buga and Cali, Valle de Cauca; I. continua from Manzanares, 



SOLEM: NEOTROPICAL LAND SNAILS 207 

Caldas east to Villavicencio, Meta; and J. oreas from the Cauca basin 
and vicinity of Villavicencio. Two of the nine Ecuadorean species 
have restricted distributions; I. hartwegi in southern Ecuador be- 
tween Guayaquil, Cuenca and the Catamayo Valley and I. aequatori- 
ana on the Amazonian slopes of the Andes from the Rio Coca in the 
North to M^ndez on the Upper Rio Paute in the south. The remain- 
ing seven species have basically overlapping ranges, living in the 
basin of the Upper Rio Esmereldas tributaries and over to the Upper 
Rio Napo and Rio Pastaza drainages on the Amazonian side. 

Of these, J. juno and /. cymatodes have the most restricted range, 
having been reported from the area between Nachiyacu, Mera and 
Nanegal. J. bourcieri has been found in the same area and as far 
north as Otovalo; /. jacksoni from Ibarra south to Sigchos and near 
both Nanegal and Mera; J. kolbergi from Ibarra to Cayandeled, 
Nanegal to Sigchos, and Napo to Mera. J. bituberculata has been 
reported from Ibarra to Chimborazo, which is almost as far south as 
Cayandeled, and also in the Esmereldas and Amazonian drainages. 
/. globosa is known from Milpe, Topo, Mera and Napo in the Ama- 
zonian area, Paramba and Huigra in the middle elevations on the 
western slopes of the Andes and the Pacific lowlands from Tumaco 
Island, Colombia south to Albanin, Rio Jubones, southern Ecuador. 
In addition to these rather well-known species, /. aloagana, I. morula, 
I. meyeri, I. aequatoria and probably /. triodonta presumably live in 
the same general area. 

It must be remembered that recorded localities are valid only for 
the general vicinity of the cited place and probably cover a number 

Table XVI 
Trans-Andean Distributions in Central Ecuador 





9t 


a 

be 


o 


03 

o 


CO 

Si 












{- 


33 


T3 


JA 


A 


o 


o 


ciS 


o 




a 

H- 1 


a 


a 


o 


(J 


a. 


o. 


E 


>> 




S 
5 


i 




a) 




o 


CD 


3 


/. bituberculata 


X 


X 


X 






X 


X 


X 


X 


I. juno 




X 






X 






X 


X 


I. bourcieri 




X 


X 


X 




X 


X 


X 


X 


I. kolbergi 


X 


X 


X 




X 


X 


X 


X 


X 


I. jacksoni 


X 


X 




X 






X 


X 


X 


I. cymatodes 




X 




X 




X 


X 


X 


X 


I. globosa 


X 




X 


X 




X 


X 


X 




I. aequatoriana 










X 


X 


X 


X 


X 


L. raimondii 






X 




X 


X 




X 


X 


L. manueli 












X 




X 


X 



208 FIELDIANA: ZOOLOGY, VOLUME 50 

of diverse ecological situations. It is very probable that distinct eco- 
logical differences separate the seven species with a trans- Andean dis- 
tribution. They do have overlapping ranges with many species having 
been reported from the same areas on both Atlantic and Pacific sides. 
In Table XVI the joint occurrences of the trans- Andean species plus 
7. aequatoriana (restricted to the Atlantic slopes) and the two Laby- 
rinthus known from the area are listed. All ten species have been 
collected near Mera, nine from Puyo, eight from Napo, seven from 
Topo and six from Nanegal. In view of the almost total lack of re- 
ports of species of Labyrinthus living in the same area (see p. 196), the 
startling concentration of Isomeria in Ecuador seems even more un- 
usual. The possibilities for ecological studies seem excellent. 

In view of the general lack of distributional data, little can be said 
about the patterns shown by the species groups. In form, 7. inex- 
pectata is nearest to J. bituberculata, although the geographic distribu- 
tion is widely separated. 7. inexpectata in the Sierra Nevada de Santa 
Marta of northern Colombia is geographically nearest to the species 
reported from Ocana — 7. fordiana and 7. continua — although not at 
all resembling them in form. The J. bituberculata group contains two 
groups, one from Colombia and the other from Ecuador. J. basidens, 
with two subspecies, and 7. neogranadensis, known only from the 
types, are species of the Cauca-Magdalena drainages and J. medemi 
is from the Sierra Nevada de Santa Marta. 7. juno, I. bituberculata 
and 7. bourcieri are part of the trans- Andean fauna of central Ecuador. 
I. hartwegi has been reported from near Guayaquil, Cuenca and the 
Catamayo Valley of southern Ecuador and could possibly be related 
to the 7. meobambensis series. 

The J. subelliptica group shows no geographic unity. 7. subellip- 
tica from central Valle de Cauca; J. continua from Caldas to Villavi- 
cencio, Meta; J. minuta from the Caldas-Tolima border area; 7. mo- 
rula and J. aloagana from central Ecuador; and 7. anodonta from 
Cajamarca, Peru might show geographic replacement, but we lack 
enough data. 

7. meobambensis and its allies range in southern Ecuador and Peru. 
7. aequatoria has been reported only from Huigra and Cayandeled in 
the Rio Chanchan valley; 7. gealei from Malacatos in the Sierra de 
Zaruma; 7. meyeri from an unknown locality; and 7. meobambensis 
was described from "Meobamba." Each species is known from essen- 
tially only one locality. 

7. oreas and its allies form the widest ranging group. 7. oreas from 
the Cauca drainage and Meta; 7. fordiana from Marmato; and 7. 



SOLEM: NEOTROPICAL LAND SNAILS 



209 



scalena from the headwaters of the Rio Magdalena in Huila are Co- 
lombian. J. stoltzmanni from southern Cajamarca, Peru is the south- 
ernmost species of Isomeria. I. kolbergi, I. jacksoni, I. cymatodes and 
/. globosa have the trans-Andean distribution, with /. globosa reach- 
ing the coastal forests of Narino, Colombia and ranging south to the 
Rio Jubones basin in Ecuador. /. aequatoriana apparently is re- 
stricted to the Amazonian side of the mountains, while no localities 
are known for /. triodonta. 



Altitudinal Zonation 

Data on the altitudinal range of Isomeria is summarized in Fig- 
ure 61. There are no recorded altitudes for /. basidens basidens, 
I. neogranadensis, I. juno, I. morula, I. aloagana, I. meobambensis, 
I. meyeri, I. triodonta, I. jacksoni, I. fordiana and I. stoltzmanni. 
Seven of the remaining species have only one recorded or inferred 
altitude range — /. inexpectata, I. medemi, I. minuta, I. bourcieri, 
I. anodonta, I. aequatoria and I. cymatodes. As in the discussion of 
Labyrinthus, in a few cases altitude records have been based on the 
evaluations of ornithological collections reported from the same vicin- 
ity (see p. 18) . 

The contrast with Labyrinthus is striking. Of the eighteen species 
with some altitudinal data, eight have not been found below 5,000 
feet; seven live substantially above 5,000 feet, but have been reported 
at lower elevations (sea level in the case of I. globosa) ; and three 
species have been found only below 5,000 feet. They are distributed: 

Above 5,000 feet Above & below 5,000 feet Below 5,000 feet 



J. inexpectata 
8,500-9,000' 

J. medemi 
8,200-8,850' 

/. basidens gudeana 
5,100-11,200' 

/. bourcieri 
8,200' 

J. minuta 
7,125' 

/. anodonta 
6,000' 

/. gealei 

5,000-7,000' 

J. scalena 
7,550-7,875' 



/. hartwegi 
3,000-8,400' 

/. aequatoria 
2,600-7,000' 

/. globosa 
0-7,500' 

J. oreas 
3,900-9,500' 

/. cymatodes 
3,900-7,800' 

J. kolbergi 
4,000-6,000' 

V". bituberculata 
4,000-13,100' 



J. continua 
3,375-4,390' 

/. subelliptica 
3,600-4,000' 

/. aequatoriana 
1,800-4,900' 



thousands 
j2 of feet 



12- 



11- 



10- 



9- 



8- 



7- 



6- 



5- 



4- 



2- 



1- 



Isomeria 



• EXE 



xx 



I 7 



rl3 



-12 



-11 



-10 



-9 



-8 



-7 



-6 



-5 



-4 



-3 



-2 



-1 



210 



SOLEM: NEOTROPICAL LAND SNAILS 211 

Obviously, with more than half of the species without altitudinal 
data or only one record, the picture will change with adequate col- 
lecting. It is clear that Isomeria is generally found at much higher 
elevations than Labyrinthus. The only true lowland species, /. glo- 
bosa, is in the Pacific lowlands, an area not reached by Labyrinthus. 
There is one record of /. aequatoriana from 1,800 feet elevation on 
the Atlantic slopes of the Andes. Twelve of the seventeen species of 
Isomeria with altitudinal data have been found at or above 7,000 feet 
elevation, which is the maximum known elevation for Labyrinthus. 
Only seven of the thirty species of Labyrinthus have been found at 
more than 5,500 feet elevation, while only three species of Isomeria 
have not been found at more than 5,500 feet elevation. 

Comparative Remarks 

Altitudinal data show a clear separation of Isomeria and Laby- 
rinthus in most areas. In the Sierra Nevada de Santa Marta of north- 
ern Colombia, the two Labyrinthus have been taken at 500-5,500 feet 
elevation and the two Isomeria at 8,200-9,000 feet. In Ecuador and 
Peru the altitudinal ranges overlap, and at several localities in Ecua- 
dor Labyrinthus raimondii, L. manueli and several species of Isomeria 
have been collected in the vicinity of the same town. We have at 
present no information as to the ecological differences between the 
species and they probably will be shown to occupy distinct vegeta- 
tional zones or microhabitats within the zones. 

In general, both Labyrinthus and Isomeria show geographic re- 
placement of the species, but the pattern of speciation seems to be 
different in the two genera and also within each genus. In Laby- 
rinthus, the isodon series is associated with mountain masses, the 
species being widely separated and restricted to the foothill region 
and lower elevation of each separate mountain area. In Costa Rica, 
L. triplicatus of the Atlantic slopes is replaced by L. quadridentatus 
on the Pacific side. In contrast, the otis series shows a wider range 





Fig. 61. Altitudinal 


range in Isomeria. 


The species are: 


1. 

2. 
3. 
4. 
5. 
6. 


/. inexpectata 

I. basidens gudeana 

I. medemi 

I. biiuberculata 

I. bourcieri 

I. hartwegi 


7. 

8. 

9. 
10. 
11. 
12. 


I. anodonia 
I. continua 
I. minuta 
I. subellipiica 
I. gealei 
I. aequatoria 


13. J. oreas 

14. /. kolbergi 

15. /. cymatodes 

16. /. scalena 

17. /. aequatoriana 

18. J. globosa 



"X" indicates only a single record; "E" an estimate based on evaluation of 
early ornithological collections. 



212 FIELDIANA: ZOOLOGY, VOLUME 50 

for individual species with a moderate amount of geographic overlap. 
Only L. plicatus, and to a lesser extent, L. marmatensis show isolation. 
The unciger series, with one lowland and one medium-elevation spe- 
cies, and the aenigmus group with its scattered species show no clear 
patterns of distribution. The very complex raimondii series may 
show geographic replacement in the Upper Amazonian Basin, but 
may equally probably be a mosaic of intergrading morphs that are 
partially ecologically segregated. 

Being primarily a group of higher altitudes, the pattern of specia- 
tion in Isomeria is of geographic replacement and isolation, with the 
major exception of the group of species with Trans-Andean distribu- 
tion in Central Ecuador (see Table XVI). Unfortunately, we do not 
have any data on their ecology at the present time. In the Rio Paez 
Valley of Huila, /. scalena has been taken at 2,400 meters elevation 
and I. oreas at 2,900 meters. This is the only case, however, where 
we have any indication of altitudinal replacement in Isomeria. 



SUMMARY 

On the basis of examination of slightly less than 2,000 specimens 
in major museum and private collections, fifty-six species of mainland 
camaenids are recognized, twenty-eight of which are placed in Laby- 
rinthus and twenty-eight in Isomeria. Four new species — Labyrin- 
thus magdalenensis, Isomeria medemi, Isomeria inexpectata, and /. 
minuta — and one new subspecies — Labyrinthus quadridentatus biol- 
leyi — are described and a new name (Isomeria jacksoni) is proposed 
for Helix atrata Pfeiffer, 1854 (not Reeve, 1852), together with many 
changes in synonymy. Only four species were available for dissection 
and only three other species had previously been studied. Anatom- 
ical variation was quite minor among the six Labyrinthus. The single 
Isomeria dissected differed only in having an apical appendage on the 
penis. All of the mainland camaenids I examined had small, hooked 
calcareous denticles on the interior ridges of the vagina and penis. 
Presumably serving a stimulatory function, no equivalent structures 
are known in other camaenids. The fragmentary anatomical evi- 
dence suggests a very close relationship for Isomeria and Labyrinthus, 
but division into two genera seems logical at this time in order to rec- 
ognize the altitudinally correlated difference in apertural configura- 
tions of the shells. Labyrinthus is a low to moderate elevation type 
in which the aperture of the adult shell is strongly constricted by 
more or less elaborate denticles and lamellae. Isomeria is a group 
of moderate to high elevations (except for /. globosa) in which the 
apertural denticles are reduced to vestigial form or are completely 
absent. J. inexpectata and /. minuta are the only species tending to 
have characters intermediate between Isomeria and Labyrinthus. 
Further anatomical studies may show that the "Isomeria" and "Laby- 
rinthus" groupings are polyphyletic and relationships cut across the 
present generic boundaries. Until the material needed for such stud- 
ies becomes available, the present classification is a practical system 
recognizing a morphological and altitudinal distinction. A phyletic 
classification is now impossible because of the lack of anatomical ma- 
terial for dissection and the total absence of ecological data for the 
vast majority of the species. 

213 



214 FIELDIANA: ZOOLOGY, VOLUME 50 

A major conclusion to be drawn from this study is that currently 
available materials of Neotropical land snail taxa are totally inade- 
quate for modern systematic studies. Most of the species and sub- 
species recognized here are known from a single locality or collection, 
48.6% of the taxa are represented in collections by less than ten indi- 
viduals and only 7.1% of the taxa by more than 100 individuals. 
Many of the species were collected only once during the last century 
and many of the type localities are sufficiently vague that they can- 
not be localized today within a fifty-mile radius. Despite the lack 
of material and data, enough evidence was obtained to suggest many 
intriguing taxonomic and ecological problems whose solution requires 
field studies. This study has been presented in its present form pri- 
marily in hope of stimulating such work. The non-marine mollusks 
are a difficult group to study because the level of systematic knowl- 
edge is very low, but they do offer unique biological problems and 
innumerable opportunities for field studies. 



Manuscript accepted for publication May 21+, 1964.. 



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1955. The American Camaenidae (Mollusca: Pulmonata). Proc. Acad. Nat. 
Sci., Philadelphia, 107, pp. 99-143, pis. 1-19. 

Zilch, Adolf 

1960. Gastropoda Euthyneura. Handbuch der Palaozoologie, 6 (2), 4: pp. 601- 
834, figs. 2112-2515. 



INDEX 

Bold face numerals indicate pages on which the principal systematic discussion 

of a taxon are included; italicized figures indicate pages on which 

illustrations of the taxon can be found. 



acutangula, Polydontes (Parthena) 20 
aenigma, Helix (Isomeria) 89 
Pleurodonte (Isomeria) 90 
aenigmus, Labyrinthus 16, 35, 37, 40, 43, 
88, 89-90, 89, 93, 103, 127, 198, 
204, 212 
aequatoria, Helix 164 
Helix (Isomeria) 164 
Isomeria 129, 148, 160, 161, 163, 164, 

165, 176, 206, 207, 208, 209 
Pleurodonte (Isomeria) 164 
aequatoriana, Helix 184, 190 
Helix (Isomeria) 188 
Isomeria 129, 130, 166, 184-190, 186, 

187, 189, 207, 208, 209, 211 
Pleurodonte (Isomeria) 188 
aesopa, Helix (Labyrinthus) triplicata 

var. 47 
aesopus, Helix 47 

Pleurodonte (Labyrinthus) 47 
aloagana, Isomeria 14, 128, 151, 152, 

15U, 155, 206, 207, 208, 209 
Ambages 35, 37, 88 

sharmani 126 
(Ambages) vexans, Labyrinthus 65 
Ammonitellinae 34, 35 
anestia, Isomeria 161 

Isomeria meobambensis form 163 
angelopolites, Labyrinthus 124, 125 
annulifera, Helix 119 

Helix (Labyrinthus) var. 119 
Pleurodonte (Labyrinthus) otis 119 
Pleurodonte (Labyrinthus) sipunculata 
119 
annuliferus, Labyrinthus 119 
anodonta, Isomeria 151, 152, 153, 156, 

160, 184, 206, 208, 209 
Ariophantopsis 35 
assimilans, Labyrinthus 93 

Labyrinthus otostomus 87, 88, 93-95, 
91* 
atrata, Helix 174, 178, 179, 213 
Helix (Isomeria) 175, 176, 179 
Isomeria 179 

Pleurodonte (Isomeria) 179 
auricoma havanensis, Zachrysia (Zachry- 

sia) 20 
auriculina, Helix 79 



baeri diminuta, Pleurodonte (Labyrin- 
thus) 78 
Helix (Labyrinthus) 81 
Labyrinthus tarapotoensis 68, 80, 81, 

82, 83, 202 
Pleurodonte (Labyrinthus) 81 
var. diminuta, Labyrinthus 75 
basidens basidens, Isomeria 138-139, 
UO, W, 145, 184, 206, 208, 209 
gudeana, Isomeria 129, 138, 139-140, 

no, ni 

Helix 138 

Helix (Isomeria) 138 
Isomeria 132, 134, 135, 138-139, no, 
HI, 142, 145, 151, 184, 206, 208, 
209 
Isomeria basidens 138-139, no, ni, 

145, 184, 206, 208, 209 
Pleurodonte (Isomeria) 138 
rugospira, Pleurodonte 139 
bifurcata, Helix 79, 87 
Helix (Labyrinthus) 87 
var., Helix 71 
bifurcatus, Labyrinthus 68, 72, 82, 83, 

87-89, 205 
biolleyi, Labyrinthus quadridentatus 1*8, 

U9, 51, 52-53, 213 
bituberculata, Dentellaria 142 
Helix 142, 148 
Helix (Isomeria) 142, 149 
Isomeria 128, 129, 130, 132, 133, 134, 
135, 136, m, 142-145, 147, 148, 
152, 153, 207, 208 
Pleurodonte (Isomeria) 144 
var. latidentata, Helix (Isomeria) 144 
var. tridentula, Helix (Isomeria) 144 
bogotensis, Helix 92 
Helix (Labyrinthus) 93 
Labyrinthus otostomus 88, 88, 89, 92, 

92-93, 126 
Pleurodonte (Labyrinthus) 93 
bourcieri, Dentellaria 149 
Helix 142, 148 
Helix (Isomeria) 144, 148 
Isomeria 59, 128, 129, 135, 145, W, 

148-150, 207, 209 
Pleurodonte (Isomeria) 149 
bowdeniana, Pleurodonte 36 



217 



218 



FIELDIANA: ZOOLOGY, VOLUME 50 



calomorpha, Helix 193 

Helix (Isomeria) 193 

Isomeria 131, 190, 193-194 

Pleurodonte (Isomeria) 193 
Camaenidae 34, 38 
Camaeninae, 35 
Caracolus 22, 23, 38 

carocolla 20 

(Labyrinthus) sieversi 71 

(Labyrinthus) uncigera var. creveauxi- 
ana 100 

marginella 20 
carocolla, Caracolus 20 
Carocolla globosa 190, 192 

hydiana 122, 123 

quadridentata 51 

subplanata 114 

uncigera 95 
chiriquiensis, Pleurodonte (Labyrinthus) 
95 

Pleurodonte (Labyrinthus) uncigera 95 
Chloritis (s.l.) 33 

cZappi, Labyrinthus 19, 21, 24, 30, 32, 33, 
35, 37, 40, 43, 44, 68, 71, 87, SS, 80, 
90-91, 126,134,198,205 

Pleurodonte (Labyrinthus) 90 
classification 34-36 

(Clathorthalicus) wallisi, Sultana 102, 200 
colombiensis, Labyrinthus 90 
continua, Helix 155 

i/eftx (Isomeria) 155 

Isomeria 128, 134, 151, 152, 155-157, 
156, 159, 160, 206, 208 

Pleurodonte (Isomeria) 155 
crassus, Hodopoeus 36 
creveauxiana, Helix 100 

Labyrinthus 19, 42, 94, 95, 96, 97, 
100-105, 198, 204 
cymatodes, Helix (Isomeria) 180 

Isomeria 128, 129, 130, 166, 170, 180, 
180-183, 181, 184, 207, 209 

parietidentata, Isomeria 180 

Pleurodonte (Isomeria) 181 

Da Costiana, Pleurodonte (Labyrinthus) 

75 
dacostiana, Pleurodonte (Labyrinthus) 

75, 80 
Dentellaria bituberculata 142 
bourcieri 149 
latidentata 142 
tridentula 142 
diminuta, Labyrinthus baeri var. 75 
Pleurodonte (Labyrinthus) baeri 78 
diminutus, Labyrinthus 21, 22, #4 (pal- 
lial region), 25, 50-31 (genitalia), 
32, 33, 35, 67, 68, 70, 75-78, 76, 79, 
82, 84, 196 
Draparnaudia 35 
dunkeri, Helix 60 

Hefrx (Labyrinthus) 60 



Labyrinthus 41, 43, 44, 45, 46, 57, 59, 

60-62, 62, 75, 99, 196, 202 
Pleurodonte (Labyrinthus) 60 

Elaphroconcha martini 153 

ellipsostoma, Helix 73 
Hefo'x (Pleurodonte) 73 
Pleurodonte (Labyrinthus) 74 

ellipsostomus, Labyrinthus 45, 67, 68, 70, 
71, 73, 73-75, 78, 198 

Endodontidae 38, 40 

Enidae 38 

equestrata, Helix 194 

Helix (Isomeria) 191, 195 
Isomeria 131, 194-195, 162 
Pleurodonte (Labyrinthus) 195 

erecta, Helix 116 

Pleurodonte (Labyrinthus) otis 117 

erectus, Labyrinthus subplanatus 113, 114, 
115, 116-119, 200 

euclausus, Labyrinthus 103, 125-126, 200 

fauna, Helix 194 

Isomeria 131, 174, 183, 186, 187, 194 
faunus, Helix (Isomeria) 194 

Pleurodonte (Isomeria) 194 

ritchieana, Isomeria 171 

var. ritchieana, Helix (Isomeria) 172 

var. ritchieana, Pleurodonte (Isomeria) 
172 
fordiana, Helix (Isomeria) 183 

Isomeria 129, 130, 166, ISO, 181, 183, 
184, 206, 208, 209 

Pleurodonte (Isomeria) 183 
fossil record 36 

fragilis, Pleurodonte (Labyrinthus) 82, 86 
frontinensis, Helix (Labyrinthus) unci- 
gera 102 
furcillata, Helix 86 

Hehx (Labyrinthus) 86 
furcillatus, Labyrinthus 68, 32, 83, 84, 
86-87, 205 

gealei, Helix 162 

Heh'x (Isomeria) 162 

Isomeria 128, 129, 160, 161, 162, 163, 

164, 206, 208 
Pleurodonte (Isomeria) 162 
genitalia 25-34 

Isomeria globosa 26, 27, 32-33 
Labyrinthus diminutus 25-30, 80, 31 
otis orthorhinus 29, 32 
unciger 28, 30-31 
globosa, Carocolla 190, 192 
#eh'x 193 

Isomeria 20, 21, 22, 25 (pallial region), 
26-27 (genitalia), 32, 34, 35, 36, 
127, 128, 130, 159, 166, 186, 190- 
193, 192, 206, 207, 209, 211, 213 
kobeltiana, Isomeria 36 
goldmani, Pleurodonte (Labyrinthus) 119 
Grabauia 34 
(Granodomus) lima, Polydontes 20 



INDEX 



219 



granulatissima, Helix (Isomeria) 172 

Isomeria 172 

Pleurodonte (Isomeria) 172 
gudeana, Isomeria basidens 129, 138, 

139-140, no, lhl 

Pleurodonte 139 
Pleurodonte (Isomeria) 139 

hartwegi, Helix 150 

Helix (Isomeria) 150 

Isomeria 128, 129, 130, 135, H7, 148, 
150-152, 207, 208 

Pleurodonte (Isomeria) 150 
havanensis, Zachrysia (Zachrysia) auri- 

coma 20 
Helicidae 34 
Helix 38 

aequatoria 164 

aequatoriana 184, 190 

aesopus 47 

annulifera 119 

a<ra/a 174, 178, 179, 213 

auriculina 79 

basidens 138 

bifurcata 79, 87 

bifurcata var. 71 

bituberculata 142, 148 

bogotensis 92 

bourcieri 142, 148 

calomorpha 193 

conJinwa 155 

creveauxiana 100 

cymatodes 180 

dunkeri 60 

ellipsostoma 73 

equestrata 194 

erecto 116 

fauna 194 

furcillatas 86 

geaZei 162 

globosa 193 

hartwegi 150 

isodon 62 

(Isomeria) aenigma 89 

(Isomeria) aequatoria 164 

(Isomeria) aequatoriana 188 

(Isomeria) atrata 175, 176, 179 

(Isomeria) basidens 138 

(Isomeria) bituberculata 142, 149 

(Isomeria) bituberculata var. latiden- 
tata 144 

(Isomeria) bituberculata var. triden- 
tula 144 

(Isomeria) bourcieri 144, 148 

(Isomeria) calomorpha 193 

(Isomeria) continua 155 

(Isomeria) cymatodes 180 

(Isomeria) equestrata 191, 195 

(Isomeria) faunus 194 

(Isomeria) faunus var. ritchieana 172 

(Isomeria) fordiana 183 

(Isomeria) gealei 162 



(Isomeria) granulatissima 172 
(Isomeria) hartwegi 150 
(Isomeria) juno 145 
(Isomeria) kolbergi 172 
(Isomeria) loxensis 150 
(Isomeria) martinii 153 
(Isomeria) mauritii 175 
(Isomeria) meobambensis 161 
(Isomeria) meyeri 164 
(Isomeria) neogranadensis 141 
(Isomeria) neogranadensis var. 139 
(Isomeria) oreas 168, 173, 181 
(Isomeria) parietidenlata 180, 182 
(Isomeria) peritropis 155, 255 
(Isomeria) scalena 183 
(Isomeria) stoltzmanni 176 
(Isomeria) subcastanea 191 
(Isomeria) subelliptica 160 
(Isomeria) triodonta 175 
(Isomeria) vexans 65 
(Isomeria) wolfi 188 
jimo 145 
labyrinthus 37, 105, 108, 122 



(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 

fera 119 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 
(Labyrinthus 



baeri 81 
bifurcata 87 
bogotensis 93 
dunkeri 60 
furcillata 86 
isodon 63 

labyrinthus 105, 115 
labyrinthus var. annuli- 



leprieurii 79 
leucodon 56 
manueli 66 
otostoma 91 
plicata var. 124 
plicatus 122 
quadridentatus 51 
raimondii 81 
subplanatus 114 
tamsiana 53 
tarapotoensis 80 
triplicate 47 
triplicata var. aesopa 47 
uncigera 95, 100 
u. frontinensis 102 

labyrinthus var. 114 

labyrinthus var. sipunculatus 119 

Le Prieurii 79 

leprieurii 79 

leucodon 55 

manoeli 66 

martini 153 

martinii 152 

meobambensis 161 

morula 152 

neogranadensis 140 

neogranatensis 140 

orais 126, 167 

ote's 37, 105 

otostomus 91 



220 



FIELDIANA: ZOOLOGY, VOLUME 50 



(Pleurodonte) ellipsostoma 73 

(Pleurodonte) yatesii 73 

plicata 108, 122 

procera 167 

quadridentala 51, 66 

raimondii 81 

sieversi 71 

stostoma 91 

subcastanea 191 

subelliptica 159 

tamsiana 53 

tarapotoensis 80 

triodonta 174 

triplicata 47 

unci g era 95 

uncigera var. anopla 95 

uncigera var. conoidea 95 

rerans 88 

yatesii 73 
Hodopoeus crassus 36 
hydiana, Carocolla 122, 123 

inexpectata, Isomeria 19, 36, 127, 128, 

129, 130, 132-134, iSS, 136, 137, 

138, 158, 206, 208, 209, 213 
isodon, Helix 62 

Heh'x (Labyrinthus) 63 

Labyrinthus 35, 40, 42, 43, 45, 46, 50, 

51, 59, 62, 65, 62-65, 66, 68, 75, 

103, 126, 133, 134, 196, 197, 198, 

205 
Pleurodonte (Labyrinthus) 63 
Isomeria 11, 12, 13, 17, 18, 20, 21, 22, 23, 

33, 34, 35, 36, 44, 88, 126-195 
aequatoria 129, 148, 160, 161, J65, 164, 

165, 176, 206, 207, 208, 209 
aequatoriana 129, 130, 166, 184-190, 

186, 187, 189, 207, 208, 209, 211 
aloagana 14, 128, 151, 152, 15k, 155, 

206, 207, 208, 209 
anestia 161 
anodonta 151, 152, 153, 156, 160, 184, 

206, 208, 209 
atrata 179 
basidens 132, 134, 135, 138-139, HO, 

142, 145, 151, 184, 206, 208, 209 
basidens gudeana 129, 138, 139-140, 

HO, m 
bituberculata 128, 129, 130, 132, 133, 

134, 135, 136, HI, 142-145, 147, 

148, 152, 153, 207, 208 
bourcieri 59, 128, 129, 135, 145, H7, 

148-150, 207, 209 
calomorpha 131, 190, 193-194 
continua 128, 134, 151, 152, 155-157, 

156, 159, 160, 206, 208 
cymatodes 128, 129, 130, 166, 170, 180, 

180-183, 181, 184,207,209 
cymatodes parietidentata 180 
equestrata 131, 162, 194-195 
fauna 131, 174, 183, 186, 187, 194 
faunus ritchieana 171 



fordiana 129, 130, 166, 180, 181, 183, 

184, 206, 208, 209 
gealei 128, 129, 160, 161, 162, 163, 

164, 206, 208 
globosa 20, 21, 22, 25 (pallial region), 

26-27 (genitalia), 32, 34, 35, 36, 

127, 128, 130, 159, 166, 186, 190- 

193, 192, 206, 207, 209, 211, 213 
globosa kobeltiana 36 
granulatissima 172 
hartwegi 128, 129, 130, 135, H7, 148, 

150-152, 207, 208 
inexpectata 19, 36, 127, 128, 129, 130, 

132-134, 133, 136, 137, 138, 158, 

206, 208, 209, 213 
jacksoni 129, 166, 173, 176, 178-180, 

180, 181, 207, 209, 213 
juno 129, 135, 145-148, H7, 151, 207, 

208 209 
kolbergi 129, 131, 166, 170, 171, 172- 

174, 177, 178, 179, 182, 194, 207, 

209 
latidentata 144 
loxensis 150 
martinii 152 
mauricei 174 
mauritii 174 
medemi 19, 91, 128, 132, 134, 135, 

136-138, 137, 139, 206, 208, 209, 

213 
meobambensis 128, 129, 130, 135, 153, 

160, 161-162, 163, 165, 195, 206, 

208, 209 
meobambensis form anestia 163 
meyeri 14, 128, 160, 161, 164-167, 

184, 206, 207, 208, 209 
minuta 36, 128, 151, 157-159, 158, 

206, 208, 209, 213 
morula 14, 128, 129, 151, 152-153, 

206, 207, 208, 209 
neogranadensis 134, 135, 138, 140-142, 

HI, 151, 184,206,208,209 
oreas 19, 128, 129, 130, 134, 165, 166, 

167-172, 170, 171, 182, 206, 207, 

208, 212 
oreas var. parvula 168, 170 
parietidentata 180, 182 
scalena 19, 128, 129, 130, 166, 183- 

184, 186, 187, 206, 209, 212 
stoltzmanni 129, 153, 166, 176-178, 

177,206, 209 
subcastanea 20, 191 
subcastanea var. kobeltiana 191 
subelliptica 128, 129, 130, 151, 152, 

157, 159, 159-161, 206, 208 
tridentula 144 
triodonta 128, 129, 164, 166, 170, 171, 

174-176, 206, 207, 209 
(Isomeria) aenigma, Helix 89 
aenigma, Pleurodonte 90 
aequatoria, Helix 164 
aequatoria, Pleurodonte 164 



INDEX 



221 



aequatoriana, Helix 188 
aequatoriana, Pleurodonte 188 
atrata, Helix 175, 176, 179 
atrata, Pleurodonte 179 
basidens, Helix 138 
basidens, Pleurodonte 138 
bituberculata, Helix 142, 149 
bituberculata, Pleurodonte 144 
bituberculata var. latidentata, Helix 144 
bituberculata var. tridentula, Helix 144 
bourcieri, Helix 144, 148 
bourcieri, Pleurodonte 149 
calomorpha, Helix 193 
calomorpha, Pleurodonte 193 
continua, Helix 155 
continua, Pleurodonte 155 
cymatodes, Helix 180 
cymatodes, Pleurodonte 181 
equestrata, Helix 191, 195 
fauna, Helix 194 
faunus, Pleurodonte 194 
faunus var. ritchieana, Helix 172 
faunus var. ritchieana, Pleurodonte 172 
fordiana, Helix 183 
fordiana, Pleurodonte 183 
gealei, Helix 162 
gealei, Pleurodonte 162 
granulatissima, Helix 172 
granulatissima, Pleurodonte 172 
gudeana, Pleurodonte 139 
hartwegi, Helix 150 
hartwegi, Pleurodonte 150 
juno, //efa'x 145 
jwno, Pleurodonte 146 
kolbergi, Helix 172 
kolbergi, Pleurodonte 172 
loxensis, Helix 150 
martinii, Helix 153 
mauritii, Helix lib 
mauritii, Pleurodonte 175 
meobambensis, Helix 161 
meobambensis, Labyrinthus 161 
meobambensis, Pleurodonte 161 
meyeri, Helix 164 
neogranadensis, Helix 141 
neogranadensis, Pleurodonte 141 
neogranadensis var., //efo'x 139 
orais, //eftx 168, 173, 181 
oreas, Pleurodonte 168 
parietidentata, Helix 180, 182 
parietidentata, Pleurodonte 181, 182 
peritropis, Helix 155, 156 
peritropis, Pleurodonte 155 
scalena, Helix 183 
scalena, Pleurodonte 184 
stoltzmanni, Helix 176 
stoltzmanni, Pleurodonte 176, 177 
suocastanea, Helix 191 
subelliptica, Helix 160 
subelliptica, Pleurodonte 160 
triodonta, Helix 175 
triodonta, Pleurodonte 175 



vexans, Helix 65 
vexans, Pleurodonte 65 
wo^, Heftx 188 

jacksoni, Isomeria 129, 166, 173, 176 

178-180, ISO, JSJ, 207, 209, 213 
jaw 22 

Isomeria globosa 22 
Labyrinthus diminutus 22 
ota's orthorhinus 22 
unciger 22 
juno, Helix 145 

//eta'x (Isomeria) 145 

Isomeria 129, 135, 145-148, 1A7, 151, 

207, 208, 209 
Pleurodonte (Isomeria) 146 

kobeltiana, Isomeria globosa 36 
Isomeria subcastanea var. 191 

kolbergi, Helix (Isomeria) 172 

Isomeria 129, 131, 166, i70, 171, 172- 

174, 177, 178, 179, 182, 194, 207, 
209 

Pleurodonte (Isomeria) 172 

Labyrinthus 11, 12, 13, 15, 17, 18, 21, 22, 
23, 32, 33, 34, 35, 36, 37-126, 129, 
131, 132, 134, 158, 159, 165, 166, 

175, 196, 208 

aenigmus 16, 35, 37, 40, 43, SS, 89-90, 

S9, 93, 103, 127, 198, 204, 212 
(.Ambages) pexaws 65 
angelopolites 124, 125 
annuliferus 119 
assimilans 93 
oaen var. diminuta 75 
bifurcatus 68, 72, S2, S3, 87-89, 205 
cfappz 19, 21, 24, 30, 32, 33, 35, 37, 40, 

43, 44, 68, 71, 87, 88, SS, S9, 90-91, 

126, 134, 198, 205 
columbiensis 90 
creveauxianus 19, 42, 94, 95, 96, 97, 

100-105, 198, 204 
diminutus 21, 22, 24 (pallial region), 

25, 30-S1 (genitalia), 32, 33, 35, 67, 

68, 70, 75-78, 76, 79, S2, 84, 196 
dunkeri 41, 43, 44, 45, 46, 57, 59, 60- 

62, 62, 75, 99, 196, 202 
ellipsostomus 45, 67, 68, 70, 71, 7S, 73- 

75, 78, 198 
euclausus 103, 125-126, 200 
furcillatus 68, 82, 83, 84, 86-87, 205 
isodon 35, 40, 42, 43, 45, 46, 50, 51, 59, 

62, 63, 62-65, 66, 68, 75, 103, 126, 

133, 134, 196, 197, 198, 205 
(Isomeria) meobambensis 161 
leprieurii 15, 45, 68, 70, 71, 72, 73, lb, 

79-80, 81, 86, 158, 202 
leucodon leucodon 42, 44, 45, 46, 50, 

55-58, 56, 57, 196, 202 
leucodon umbrus 45, 55, 56, 57, 58-59, 

202 



222 



FIELDIANA: ZOOLOGY, VOLUME 50 



magdalenensis 40, 41, 42, 43, 44, 45, 

46, U8, A9, 59-60, 62, 88, 135, 149, 

196, 202, 213 
manceli 66 
manueli 42, 44, 45, 59, 62, 63, 65, 66- 

67,88,196,198,204,211 
marmatensis 41, 42, 103, 104, 123, 12k, 

124-125, 126,200,212 
otis orthorhinus 15, 16, 17, 19, 20, 21, 

22 (jaw), 21+ (pallial region), 29 

(genitalia), 32, 33, 34, 38, 104, 105, 

108-111, 110, 111, 116, 123, 124, 

176, 200, 202 
otis otis 19, 41, 42, 43, 61, 103, 104, 

105-108, 110, 111, 113, 116, 123, 

200, 201, 204 
otostomus assimilans 87, 88, 93-95, 9k 
otostomus bogotensis 88, 88, 89, 92, 92- 

93, 126 
otostomus otostomus 40, 42, 43, 87, 88, 

88, 89, 91-92, 92, 126, 129, 162, 198 
plicatus 20, 21, 24, 25, 28, 31, 32, 33, 

42, 44, 103, 104, 105, Ilk, 120, 122- 

124, 12k, 125, 196, 200, 201, 212 
pronus 68, 70, 75, 78, 78-79, 84, 198, 

202 
quadridentata 66 
quadridentatus biolleyi k8, k9, 51, 52- 

53, 213 
quadridentatus quadridentatus 44, 45, 

46, k8, k9, 50, 51-52, 55, 56, 196, 

202 211 
raimondii 41, 42, 43, 68, 70, 71, 79, 

81-86, 82, 83, 84, 87, 88, 179, 196, 

198, 204, 211, 212 
sharmani 37, 88, 9k, 126, 200 
sieversi 19, 37, 40, 43, 44, 51, 61, 63, 

68, 71, 72, 91, 134, 138, 198, 204 
sp. 40, 68, 71-72, 76, 205 
subplanatus 41, 42, 103, 113, 123, 200 
subplanatus erectus US, Ilk, 115, 1 16— 

119, 200 
subplanatus sipunculatus 40, 114, 115, 

119, 122, 120, 121,200 
subplanatus subplanatus 104, 113, Ilk, 

114-116, 115, 117, 204 
tamsianus 15, 20, 21, 25, 28, 32, 33, 

40, 42, 44, 46, 53-55, 56, 57, 196, 

202 
tarapotoensis 68, 70, 82, 83 
tarapotoensis baeri 68, 80, 81, 82, 83, 

202 
tarapotoensis tarapotoensis 80, 81, 82, 

87 
triplicatus 45, 46, 47-50, k8, k9, 51, 

53, 55, 196, 211 

unciger 15, 17, 19, 20, 21, 22 (jaw), 24, 
25 (pallial region), 28 (genitalia), 
33, 38, 41, 42, 43, 61, 94, 95-100, 
96, 98, 102, 126, 198, 202, 212 

unciger chiriquiensis 96, 98 



var. sipunculatus, Helix 119 
vexans 35, 42, 45, 46, 62, 63, 65, 88, 
89, 93, 126, 127, 134, 198, 204 
(Labyrinthus) aesopus, Pleurodonte 47 
baeri diminuta, Pleurodonte 78 
baeri, Helix 81 
baeri, Pleurodonte 81 
bifurcata, Helix 87 
bogotensis, Helix 93 
bogotensis, Pleurodonte 93 
chiriquiensis, Pleurodonte 95 
clappi, Pleurodonte 90 
Da Costiana, Labyrinthus 75 
dacostiana, Pleurodonte 75, 80 
dunkeri, Pleurodonte 60 
ellipsostoma, Pleurodonte 74 
equestrata, Pleurodonte 195 
fragilis, Pleurodonte 82, 86 
furcillata, Helix 86 
goldmani, Pleurodonte 119 
isodon, Helix 63 
isodon, Pleurodonte 63 
labyrinthus, Helix 105, 115 
labyrinthus, Pleurodonte 105, 108 
labyrinthus var. annulifera, Helix 119 
leprieurii, Helix 79 
leprieurii, Pleurodonte 79 
leucodon, Helix 56 
leucodon, Pleurodonte 56 
manueli, Helix 66 
manueli, Pleurodonte 66 
manuelis, Pleurodonte 82 
martinii, Pleurodonte 153 
otis annulifera, Pleurodonte 119 
otis erecta, Pleurodonte 117 
otis, Pleurodonte 105 
otis sipunculata, Pleurodonte 119 
otis subplanatus, Pleurodonte 115 
otostoma, Helix 91 
otostoma, Pleurodonte 91 
plicata marmatensis, Pleurodonte 124 
plicata, Pleurodonte 108, 122 
plicata var., //efo'x 124 
plicatus, Helix 122 
quadridentatus, Helix 51 
quadridentatus, Pleurodonte 51 
raimondii, Helix 81 
sieversi, Caracolus 71 
sieversi, Pleurodonte 71 
sipunculata annulifera, Pleurodonte 119 
sipunculata, Pleurodonte 119 
subcastanea, Pleurodonte 191 
subplanatus, Helix 114 
tamsiana, Helix 53 
tamsiana, Pleurodonte 53 
tarapotoensis, Helix 80 
tenaculum, Pleurodonte 95 
triplicate, Helix 47 
triplicata var. aesopa, Helix 47 
triplicatus, Pleurodonte 47 
uncigera chiriquiensis, Pleurodonte 95 
uncigera frontinensis, Helix 102 



INDEX 



223 



uncigera, Helix 95, 100 

uncigera, Pleurodonie 95 

uncigera var. creveauxiana, Caracolus 
100 

yatesi, Pleurodonie 73 
labyrinthus var. annulifera, Helix (Laby- 
rinthus 119 

Helix 37, 105, 108, 122 

Helix (Labyrinthus) 105, 115 

var., Helix 114 

Pleurodonte 108 

Pleurodonie {Labyrinthus) 105, 108 
latidentata, Dentellaria 142 

/Yeftx (Isomeria) bituberculata var. 144 

Isomeria 144 
Le Prieurii, Helix 79 
leprieurii, Helix 79 

Heftx (Labyrinthus) 79 

Labyrinthus 15, 45, 68, 70, 71, 72, 75, 
75, 79-80, 81, 86, 158, 202 

Pleurodonte (Labyrinthus) 79 
leucodon, Helix 55 

//eh'x (Labyrinthus) 56 

Labyrinthus leucodon 42, 44, 45, 46, 
50, 55-58, 56, 57, 196, 202 

Pleurodonte (Labyrinthus) 56 

umbrus, Labyrinthus 45, 55, 55, 57, 
58-59, 202 
life history 19-20 
lima, Polydontes (Granodomus) 20 
loxensis, Helix (Isomeria) 150 

Isomeria 150 
Lucerna 38 

luquillensis, Polydontes (Luquillia) 20 
(Luquillia) luquillensis, Polydontes 20 
Lyriostoma 37 
Lyrostoma 37 

magdalenensis, Labyrinthus 40, 41, 42, 
43, 44, 45, 46, 45, -49, 59-60, 62, 88, 
135, 149, 196, 202, 213 
manceli, Labyrinthus 66 
manoeli, Helix 66 
manueli, Helix (Labyrinthus) 66 

Labyrinthus 42, 44, 45, 59, 62, 55, 65, 

66-67, 88, 196, 198, 204, 211 
Pleurodonte (Labyrinthus) 66 
manuelis, Pleurodonte (Labyrinthus) 82 
marginella, Caracolus 20 
marmatensis, Labyrinthus 41, 42, 103, 
104, 123, 12k, 124-125, 126, 200, 
212 
Pleurodonte (Labyrinthus) plicata 124 
martini, Elaphroconcha 153 

Helix 153 
martinii, Helix 152 
He/zx (Isomeria) 153 
Isomeria 152 

Pleurodonte (Labyrinthus) 153 
mauricei, Isomeria 174 
mauritii, Helix (Isomeria) 175 
Isomeria 174 



Pleurodonte (Isomeria) 175 
medemi, Isomeria 19, 91, 128, 132, 134, 
135, 136-138, 237, 139, 206, 208, 
209, 213 
meobambensis form anestia, Isomeria 163 
Helix 161 

//eh'x (Isomeria) 161 
Isomeria 128, 129, 130, 135, 153, 160, 
161-162, 265, 165, 195, 206, 208, 
209 
Labyrinthus (Isomeria) 161 
Pleurodonte (Isomeria) 161 
meyeri, Helix (Isomeria) 164 

Isomeria 14, 128, 160, 161, 164-167, 
184, 206, 207, 208, 209 
minuta, Isomeria 36, 128, 151, 157-159, 

155, 206, 208, 209, 213 
morula, Helix 152 

Isomeria 14, 128, 129, 151, 152-153, 

206, 207, 208, 209 

neogranadensis, Helix 140 

Helix (Isomeria) 141 

Isomeria 134, 135, 138, 140-142, HI, 
151, 184, 206, 208, 209 

Pleurodonte (Isomeria) 141 

var., Helix (Isomeria) 139 
neogranatensis, Helix 140 

Odontostominae 38 

oreas, Helix 126, 

tfeZz'x (Isomeria) 168, 173, 181 
Isomeria 19, 128, 129, 130, 134, 165, 
166, 167-172, 2 70, 2 72, 182, 206, 

207, 208, 212 
Pleurodonte (Isomeria) 168 
var. parvula, Isomeria 168, 170 

Oreohelicinae 35 

orthorhinus, Labyrinthus otis 15, 16, 17, 
19, 20, 21, 22 (jaw), 2k- (pallial re- 
gion), 29 (genitalia), 32, 33, 34, 38, 
104, 105, 108-111, 110, 111, 116, 
123, 124, 176, 200, 202 
Pleurodonte (Labyrinthus) otis 108 
otis annulifera, Pleurodonte (Labyrin- 
thus) 119 
erecta, Pleurodonte (Labyrinthus) 117 
Helix 37, 105 
Labyrinthus otis 19, 41, 42, 43, 61, 

103, 104, 105-108, 110, 111, 113, 
116, 123,200,202,204 

orthorhinus, Labyrinthus 15, 16, 17, 
19, 20, 21, 22 (jaw), 2k (pallial re- 
gion), 29 (genitalia), 32, 33, 34, 38, 

104, 105, 108-111, 110, 111, 116, 
123, 124, 176, 200, 202 

orthorhinus, Pleurodonte (Labyrinthus) 

108 
Pleurodonte (Labyrinthus) 105 
sipunculata, Pleurodonte (Labyrinthus) 

119 



224 



FIELDIANA: ZOOLOGY, VOLUME 50 



subplanatus, Pleurodonte (Labyrinthus) 

115 
otostoma, Helix (Labyrinthus) 91 

Pleurodonte (Labyrinthus) 91 
otostomus assimilans, Labyrinthus 87, 88, 

93-95, 9U 
bogotensis, Labyrinthus 88, 88, 89, 92, 

92-93, 126 
Helix 91 
Labyrinthus otostomus 40, 42, 43, 87, 

88, 88, 89, 91-92, 92, 126, 129, 162, 

198 

pallial region 23-25 

Isomeria globosa 25 

Labyrinthus diminutus 21* 
otis orthorhinus 2k 
unciger 25 
parietidentata, Helix (Isomeria) 180, 182 

Isomeria 180, 182 

Isomeria cymatodes 180 

Pleurodonte (Isomeria) 181, 182 
(Parthena) acutangula, Polydontes 20 
peritropis, Helix (Isomeria) 155 

Pleurodonte (Isomeria) 155, 156 
Pleurodonte 25, 34, 36, 38 

basidens rugospira 139 

bowdeniana 36 

gudeana 139 

(Isomeria) aenigma 90 

(Isomeria) aequatoria 164 

(Isomeria) aequatoriana 188 

(Isomeria) atrata 179 

(Isomeria) basidens 138 

(Isomeria) bituberculata 144 

(Isomeria) bourcieri 149 

(Isomeria) calomorpha 193 

(Isomeria) continua 155 

(Isomeria) cymatodes 181 

(Isomeria) faunus 194 

(Isomeria) jaunus var. ritchieana 172 

(Isomeria) fordiana 183 

(Isomeria) gealei 162 

(Isomeria) granulatissima 172 

(Isomeria) gudeana 139 

(Isomeria) hartwegi 150 

(Isomeria) juno 146 

(Isomeria) kolbergi 172 

(Isomeria) mauritti 175 

(Isomeria) meobambensis 161 

(Isomeria) neogranadensis 141 

(Isomeria) oreas 168 

(Isomeria) parietidentata 181, 182 

(Isomeria) peritropis 155 

(Isomeria) scalena 184 

(Isomeria) stoltzmanni 176 

(Isomeria) subelliptica 160 

(Tsomm'a) triodonta 175 

(Isomeria) vexans 65 

labyrinthus 108 

(Labyrinthus) aesopus 47 

(Labyrinthus) baeri 81 



(Labyrinthus) baeri diminuta 78 
(Labyrinthus) bogotensis 93 
(Labyrinthus) chiriquiensis 95 
(Labyrinthus) clappi 90 
(Labyrinthus) Da Costiana 75 
(Labyrinthus) dacostiana 75, 80 
(Labyrinthus) dunkeri 60 
(Labyrinthus) ellipsostoma 74 
(Labyrinthus) equestrata 195 
(Labyrinthus) fragilis 82 
(Labyrinthus) goldmani 119 
(Labyrinthus) isodon 63 
(Labyrinthus) labyrinthus 105, 108 
(Labyrinthus) leprieurii 79 
(Labyrinthus) leucodon 56 
(Labyrinthus) martinii 153 
(Labyrinthus) manueli 66 
(Labyrinthus) manuelis 82 
(Labyrinthus) otis 105 
(Labyrinthus) otis annulifera 119 
(Labyrinthus) otis erecta 117 
(Labyrinthus) otis orthorhinus 108 
(Labyrinthus) otis sipunculata 119 
(Labyrinthus) otis subplanatus 115 
(Labyrinthus) otostoma 91 
(Labyrinthus) plicata 108, 122 
(Labyrinthus) plicata marmatensis 124 
(Labyrinthus) quadridentatus 51 
(Labyrinthus) sieversi 71 
(Labyrinthus) sipunculata 119 
(Labyrinthus) sipunculata annulifera 

119 
(Labyrinthus) subcastanea 191 
(Labyrinthus) tamsiana 53 
(Labyrinthus) tenaculum 95 
(Labyrinthus) triplicatus 47 
(Labyrinthus) uncigera 95 
(Labyrinthus) uncigera chiriquiensis 95 
(Labyrinthus) yatesi 73 

(Pleurodonte) ellipsostoma, Helix 73 
yatesii, Helix 73 

Pleurodontites 36 

plicata, Helix 108, 122 

plicata marmatensis, Pleurodonte (Laby- 
rinthus) 124 

plicata, Pleurodonte (Labyrinthus) 108, 
122 

plicata var. Hefe (Labyrinthus) 124 

plicatus, Helix (Labyrinthus) 122 

plicatus, Labyrinthus 20, 21, 24, 25, 28, 
31, 32, 33, 42, 44, 103, 104, 105, 
iU, -720, 122-124, in, 125, 196, 
200, 201, 212 

Polydontes 22 

(Granodomus) lima 20 
(Luquillia) luquillensis 20 
(Parthena) acutangula 20 

Polygyratia 35 

Polygyridae 38 

procera, Helix 167 

pronus, Labyrinthus 68, 70, 75, 75, 78- 
79, 84, 198, 202 



INDEX 



225 



Pupillidae 38, 40 

quadridentata, Carocolla 51 

quadridentata, Helix 51, 66 

quadridentata, Labyrinthus 66 

quadridentatus biolleyi, Labyrinthus 48 
49, 51, 52-53, 213 

quadridentatus, Helix (Labyrinthus) 51 

quadridentatus, Labyrinthus quadriden- 
tatus 44, 45, 46, 48, 49, 50, 51-52, 
55, 56, 196, 202, 211 

quadridentatus, Pleurodonte (Labyrin- 
thus) 51 

radulae 21 

Isomeria globosa 21 
Labyrinthus diminutus 21 

otis orthorhinus 21 

unciger 21 
raimondii, Helix 81 
raimondii, Helix (Labyrinthus) 81 
raimondii, Labyrinthus 41, 42, 43, 68, 

70, 71, 79, 81-86, 82, 83, 84, 87, 88, 

179, 196, 198, 204, 211, 212 
ritchieana, Isomeria faunus 171 
rugospira, Pleurodonte (sic) basidens 139 

scalena, Helix (Isomeria) 183 

scalena, Isomeria 19, 128, 129, 130, 166, 

183-184, 186, 187, 206, 209, 212 
scalena, Pleurodonte (Isomeria) 184 
sharmani, Ambages 126 
sharmani, Labyrinthus 37, 88, 94, 126, 

200 
sieversi, Caracolus (Labyrinthus) 71 
sieversi, Helix 71 
sieversi, Labyrinthus 19, 37, 40, 43, 44, 

51, 61, 63, 68, 71, 72, 91, 134, 138, 

198, 204 
sieversi, Pleurodonte (Labyrinthus) 71 
sipunculata annulifera, Pleurodonte 

(Labyrinthus) 119 
sipunculata, Pleurodonte (Labyrinthus) 

119 
sipunculata, Pleurodonte (Labyrinthus) 

otis 119 
sipunculatus, Helix labyrinthus var. 119 
sipunculatus, Labyrinthus subplanatus 

40, 114, 115, 119-122, 120, 121,200 
Solaropsis 35 

sp., Labyrinthus 40, 68, 71-72, 76, 205 
Stegodera 34 

stoltzmanni, Helix (Isomeria) 176 
stoltzmanni, Isomeria 129, 153, 176-178, 

177, 166,206,209 
stoltzmanni, Pleurodonte (Isomeria) 176, 

176 
stostoma, Helix 91 
Strobilopsidae 38 
subcastanea, Helix 191 
subcastanea, Helix (Isomeria) 191 
subcastanea, Isomeria 20, 191 



subcastanea, Pleurodonte (Labyrinthus) 

191 
subcastanea var. kobeltiana, Isomeria 191 
subelliptica, Helix 159 
subelliptica, Helix (Isomeria) 160 
subelliptica, Isomeria 128, 129, 130, 151, 

152, 157, 159, 159-161, 206, 208 
subelliptica, Pleurodonte (Isomeria) 160 
subplanata, Caracolla 114 
suplanatus erectus, Labyrinthus 113, 114, 

115, 116-119, 200 
subplanatus, Helix (Labyrinthus) 114 
subplanatus, Labyrinthus 41, 42, 103, 

113, 123, 200 
subplanatus, Labyrinthus subplanatus 

104, 114, 114-116, 113, 115, 117, 

204 
subplanatus, Pleurodonte (Labyrinthus) 

otis 115 
subplanatus sipunculatus, Labyrinthus 

40, 114, 115, 119-122, 120, 121, 200 
Sultana (Clathorthalicus) wallisi 102, 200 

tamsiana, Helix 53 
tamsiana, Helix (Labyrinthus) 53 
tamsiana, Pleurodonte (Labyrinthus) 53 
tamsianus, Labyrinthus 15, 20, 21, 25, 
28, 32, 33, 40, 42, 44, 46, 53-55, 

56, 57, 196, 202 
tarapotoensis, Helix 80 
tarapotoensis, Helix (Labyrinthus) 80 
tarapotoensis, Labyrinthus 68, 70, 82, 83 
tarapotoensis, Labyrinthus tarapotoensis 

80, 81, 82, 87 

tenaculum, Pleurodonte (Labyrinthus) 95 

Tornatellinidae 38 

Traumatophora 34 

tridentula, Dentellaria 142 

tridentula, Helix (Isomeria) bituberculata 
var. 144 

tridentula, Isomeria 144 

triodonta, Helix 174 

triodonta, Helix (Isomeria) 175 

triodonta, Isomeria 128, 129, 164, 166, 
i70, 171, 174-176, 206, 207, 209 

triodonta, Pleurodonte (Isomeria) 175 

triplicata, Helix 47 

triplicate, Helix (Labyrinthus) 47 

triplicata var. aesopa, Helix (Labyrin- 
thus) 47 

triplicatus, Labyrinthus 45, 46, 47-50, 
4S, 49, 51, 53, 55, 196, 211 

triplicatus, Pleurodonte (Labyrinthus) 47 

umbrus, Labyrinthus 58 

umbrus, Labyrinthus leucodon 45, 55, 56, 

57, 58-59, 202 

unciger, Labyrinthus 15, 17, 19, 20, 21, 
22 (jaw), 24, 25 (pallial region), 
28 (genitalia), 33, 38, 41, 42, 43, 
61, 96, 98, 94, 95-100, 102, 126, 
198, 202, 212 



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FIELDIANA: ZOOLOGY, VOLUME 50 



uncigera, Caracolla 95 

uncigera chiriquiensis, Pleurodonte (Laby- 

rinthus) 95 
uncigera frontinensis, Helix (Labyrin- 

thus) 102 
uncigera, Helix 95 

uncigera, Helix (Labyrinthus) 95, 100 
uncigera, Pleurodonte (Labyrinthus) 95 
uncigera var. anopla, Helix 95 
uncigera var. conoidea, Helix 95 
uncigera var. creveauxiana, Caracolus 

(Labyrinthus) 100 

var. anopla, Helix uncigera 95 
var. conoidea, Helix uncigera 95 
var. creveauxiana, Caracolus (Labyrin- 
thus) uncigera 100 
vexans, Helix 88 



vexans, Helix (Isomeria) 65 

vexans, Labyrinthus 35, 42, 45, 46, 62, 

65, 65, 88, 89, 93, 126, 127, 134, 

198, 204 
vexans, Labyrinthus (Ambages) 65 
vexans, Peurodonte (Isomeria) 65 

wallisi, Sultana (Clathorthalicus) 102, 200 
wolfi, Helix (Isomeria) 188 

yatesii, Helix 73 

yatesii, Helix (Pleurodonte) 73 

yatesii, Pleurodonte (Labyrinthus) 73 

Zachrysia (Zachrysia) auricoma havanen- 

sis 20 
Zonitidae 38 



Publication 1008